Medical apparatus

ABSTRACT

A medical apparatus according to the present invention includes: a flexible sheath; an arm section having a bending part capable of bending operation and a first channel capable of inserting a procedure instrument therethrough, the arm section being disposed to protrude from a tip of the sheath; and an operation stick having a second channel connected to the first channel and a bending operating part connected to the arm section by an operation-transmission member, wherein the operation stick has: a regulation section for regulating movement of the bending operating part; and a falloff-preventive section for engaging with the procedure instrument inserted in the second channel to prevent the procedure instrument from falling from the operation stick.

CROSS REFERENCE TO RELATED APPLICATIONS

This is a Continuation In-part Application (CIP) based on U.S. patentapplication Ser. No. 12/035,535, titled “MEDICAL TREATMENT ENDOSCOPE”,filed Feb. 22, 2008, which is a CIP based on U.S. patent applicationSer. No. 11/809,488, titled “MEDICAL TREATMENT ENDOSCOPE”, filed Jun. 1,2007, which is a CIP based on U.S. patent application Ser. No.11/652,880, titled “MEDICAL TREATMENT ENDOSCOPE”, filed Jan. 12, 2007,which is a CIP based on U.S. patent application Ser. No. 11/435,183,titled “MEDICAL TREATMENT ENDOSCOPE”, filed May 16, 2006, which is a CIPbased on U.S. patent application Ser. No. 11/331,963, titled “MEDICALTREATMENT ENDOSCOPE”, filed Jan. 13, 2006, the content of which isincorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a medical apparatus used to be insertedin to a body cavity.

2. Background Art

Laparoscopic surgery is a conventionally known technique that has beenemployed when performing a medical procedure such as observation ortreatment of the internal organs of the human body. Rather than making alarge abdominal incision, laparoscopic surgery allows for the procedureto be carried out by making several openings in the abdominal wall, andinserting a laparoscope and surgical instruments such as forceps intothese openings. This type of surgery offers the benefit of being lessinvasive on the patient, since only small openings are made in theabdominal wall.

As a method of even further reducing stress on the patient, it has beenproposed in recent years to carry out medical procedures by inserting aflexible endoscope into the patient via a natural opening such as themouth, nostrils or anus. An example of a medical treatment endoscopeused in such procedures is disclosed in U.S. Patent ApplicationPublication No. 2005/0065397.

In the medical treatment endoscope disclosed in this reference, armmembers that have a bendable end are respectively inserted into aplurality of lumens disposed within a flexible inserted part that isinserted into the body via the mouth of the patient. By insertingrespective instruments through these arm members, the procedure site ofinterest can be approached from different directions with the variousinstruments. Accordingly, a plurality of procedures can be carried outin continuum by means of a single endoscope inserted into the body.

SUMMARY OF THE INVENTION

A medical apparatus according to the present invention includes: aflexible sheath; an arm section having a bending part capable of abending operation and a first channel capable of inserting a procedureinstrument therethrough, the arm section being disposed to protrude froma tip of the sheath; and an operation stick having a second channelconnected to the first channel and a bending operating part connected tothe arm section by an operation-transmission member, wherein theoperation stick has: a regulation section for regulating movement of thebending operating part; and a falloff-preventive section for engagingwith the procedure instrument inserted in the second channel to preventthe procedure instrument from falling from the operation stick.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view showing a medical treatment endoscopeaccording to a first embodiment.

FIG. 2 is an enlarged view of an operation section.

FIG. 3 is a view taken along the line A-A in FIG. 2 in parallel with anaxial direction of a first operation section.

FIG. 4 is a view on arrow AB in FIG. 3.

FIG. 5 is a cross-sectional view along the line AC-AC in FIG. 4.

FIG. 6 is a cross-sectional view along the line AD-AD in FIG. 4.

FIG. 7 is an exploded view for a rotational axis.

FIG. 8 is a perspective view for the other rotational axis, a supportchip, and a bending wire.

FIG. 9 is a cross-sectional view along the line AE-AE in FIG. 8.

FIG. 10 is a plan view illustrating a first operation stick and aprocedure instrument.

FIG. 11 is a cross-sectional view along the line AF-AF in FIG. 10illustrating a pre-insertion state of the procedure instrument.

FIG. 12 is a perspective view for a piston.

FIG. 13 is a cross-sectional view showing an enlarged state of a firstoperation stick illustrated in FIG. 6.

FIG. 14 shows a channel in magnified view.

FIG. 15 is a plan view illustrating a procedure instrument.

FIG. 16 is a cross-sectional view along the line AG-AG in FIG. 15.

FIG. 17 describes how to attach a protection member to a ring.

FIG. 18 describes a post-attached protection member disposed to thering.

FIGS. 19A and 19B illustrate a cam in a perspective view.

FIG. 20 is a view on arrow AH in FIG. 19.

FIG. 21 is a cross-sectional view along the line AI-AI in FIG. 15.

FIG. 22 is a cross-sectional view along the line AJ-AJ in FIG. 15.

FIG. 23 illustrates motions provided by a cam, a piston, and aconnection plate when the procedure instrument is inserted into thefirst operation stick.

FIG. 24 illustrates the piston pushed up by the cam.

FIG. 25 illustrates the connection plate in a retractable state.

FIG. 26 illustrates the cam disposed between two grooves of theconnection plate.

FIG. 27 illustrates an engaged state of the cam to a second groove.

FIG. 28 illustrates the cam pushing up the piston when removing theprocedure instrument.

FIG. 29 illustrates the piston pushed up by rotating the cam.

FIG. 30 illustrates a base having an operation section joined to asecond bending slider disposed on a side of a base.

FIG. 31 is a cross-sectional view illustrating a mechanism for joiningthe second bending slider to the operation section in the configurationshown in FIG. 30.

FIG. 32 shows a modified example of the cam.

FIG. 33 illustrates a feed operation for the procedure instrument.

FIG. 34 illustrates a feed operation for the procedure instrument.

FIG. 35 illustrates a combined use of the medical treatment endoscopeand an overtube.

FIG. 36 shows the structure of the medical treatment endoscope accordingto the second embodiment of the present invention.

FIG. 37 shows an operation stick of the medical treatment endoscope.

FIG. 38 is a perspective view showing a channel unit removed from anoperation stick.

FIG. 39 is a cross-sectional view of the operation stick.

FIG. 40 shows the vicinity of a channel-fixing section of the operationsection of the medical treatment endoscope.

FIG. 41 is a perspective view showing the sterilized channel unit.

FIG. 42 shows the channel unit inserted into the operation section.

FIG. 43 is a cross-sectional view showing the connection section of thechannel unit and the channel-fixing section.

FIG. 44 shows operation of disposing a drape onto the operation section.

FIG. 45 shows the operation section covered by the drape.

FIG. 46 shows a first cap removed from the connection section.

FIG. 47 shows the channel unit connected to the treatment instrumentchannel.

FIG. 48 shows the channel unit and an erroneous-movement-preventivesection of the operation stick prior to insertion of the treatmentinstrument.

FIG. 49 shows the channel unit and the erroneous-movement-preventivesection of the operation stick when the treatment instrument isinserted.

FIG. 50 shows the channel unit and the erroneous-movement-preventivesection of the operation stick when a slider is drawn.

FIG. 51 shows the channel unit and the erroneous-movement-preventivesection of the operation stick when the slider is fixed.

FIG. 52 shows the channel unit and the erroneous-movement-preventivesection of the operation stick when the treatment instrument is furtherinserted.

FIG. 53 shows a removal button and channel unit of the operation stick.

FIG. 54 shows the channel unit and the erroneous-movement-preventivesection of the operation stick when the removal button is pressed.

FIG. 55 is a bottom plan view showing an operation stick and a channelunit in accordance with a modified example of the medical treatmentendoscope.

FIG. 56 is a cross-sectional view along the line A-A in FIG. 55.

FIG. 57 is a cross-sectional view along the line B-B in FIG. 55.

FIG. 58 shows the channel unit and an instrument channel in accordancewith the modified example of the medical treatment endoscope.

FIG. 59 is perspective view showing a connection section of the channelunit.

FIGS. 60A and 60B are cross-sectional views showing the channel unit inaccordance with the modified example of the present invention.

FIG. 61 is a perspective view showing the channel unit in the medicaltreatment endoscope according to a third embodiment of the presentinvention.

FIG. 62 is a cross-sectional view of the channel unit.

FIG. 63 is a cross-sectional view of the channel pipe of the channelunit in magnified view.

FIG. 64 is a perspective view showing an operation stick having achannel unit inserted therethrough.

FIG. 65 is a cross-sectional view of the operation stick having thechannel unit inserted therethrough.

FIG. 66 is a perspective view showing a main body of the operation stickin magnified view.

FIG. 67 shows a tip of the operation stick attached to the operationsection.

FIG. 68 shows a removal button of the operation unit.

DETAILED DESCRIPTION OF THE INVENTION

Embodiments of the present embodiment will be described as follows. Thebasic structure of a medical treatment endoscope as an example of amedical apparatus of the present invention is disclosed by thecorresponding U.S. patent application Ser. Nos. 11/331,963, 11/435,183,and 11/652,880 of the present patent application. Disclosure by theseapplications is incorporated into the following explanation.

First Embodiment

A medical treatment endoscope according to the present embodiment isfunctionally divided into an operation section for conducting necessarytreatments by means of arm sections and procedure instruments; and anendoscope operation section for operating an endoscope. The presentembodiment features operation sections that are operable in separatelocations from the endoscope. An operation section built in an endoscopeoperation section necessitates an operator conducting all the operationsalone, i.e., inevitably complex operations. The present embodimentenables two operators to share operations, i.e., operating an endoscopeand conducting a treatment; thus, facilitating the operations.

As illustrated in FIG. 1, an endoscope insertion section 503 fullyintegrated with a medical treatment endoscope 501 extends from an end ofan endoscope insertion section 502. An elongated and flexible endoscopeinsertion section 503 has the same structure as those of the U.S. patentapplication Ser. Nos. 11/435,183 and 11/652,880. That is, the endoscopeinsertion section 503 has a first sheath 301 having a first arm section302A and a second arm section 302B on the tip of the first sheath 301.Treatment sections 505A and 505B of procedure instruments 504A and 504Beach protrude from the tips of the arm sections 302A and 302B. A firstbending part 306 and a second bending part 308, in this order from thetips of the arm sections 302A and 302B, are formed to each arm section302A and 302B. Combined use with a third bending section 203B formed inthe first sheath 301 enables a bending operation in a human body. Thefirst and second arm members 302A and 302B may be inserted into anothersheath protruding from the tip of the sheath 301 as disclosed by theU.S. patent application Ser. No. 11/652,880. Meanwhile, an operationsection 520 is enlarged in FIG. 1 to help better understanding.

A forceps cap 510 is provided to a side of the endoscope insertionsection 502 near an end that continues to the endoscope insertionsection 503. The forceps cap 510 communicates to an operation channelformed in the first sheath 301. Inserting another procedure instrument,which is not shown in the drawing, from here enables the procedureinstrument to protrude from the tip of the endoscope insertion section503. In addition, disposed to the endoscope insertion section 502 are aswitch 511, an angle knob 512, and a universal cable 513 that isconnected to a control apparatus that is not shown in the drawing. Forexample, operating the switch 511 provides air-supply, water-supply, andsuction through a channel formed in the first sheath 301. Operating theangle knob 512 bends the third bending section 203B into four directionwith respect to an axial line.

In addition, an elongated flexible connection sheath 515 extends fromthe other end of the endoscope insertion section 502. An operationsection 520 is disposed at an end of a connection sheath 515.

The operation section 520 has a base 521 that fixes the connectionsheath 515. Attached to the base 521 are a first operation unit 530A anda second operation unit 530B. The first operation unit 530A has anoperation stick 531A into which an operation section 506A of theprocedure instrument 504A is inserted. The procedure instrument 504A ispassed through the first arm member 302A. The operation section 506A issupported by the operation stick 531A so as to be capable of extendingand retracting in the axial line and bending in four directions withrespect to the axial line. The second operation unit 530B has anoperation stick 531B into which an operation section 506B of theprocedure instrument 504B is inserted. The procedure instrument 504B ispassed through the second arm member 302B. The operation section 506B issupported by the operation stick 531B so as to be capable of extendingand retracting in the axial line and bending in four directions withrespect to the axial line. Furthermore, the operation section 520 fixedto an operation bed enables operation of the first second operation unit530A and the second operation unit 530B.

As illustrated in FIG. 2 in an enlarged view, the operation units 530Aand 530B are disposed diagonally so that portions closer to theconnection sheath 515 are placed closer to each other. Two operationsections 506A and 506B (or two operation sticks 531A and 531B) aredisposed at angles between 20° and 100°. Disposing the operationsections 506A and 506B with the opening angle relative to an operatorfacilitates the operator's operation, thus improving operability. Inaddition, the width of the operation section 520 closer to theconnection sheath 515 can be reduced. Also, as disclosed by U.S. patentapplication Ser. No. 11/652,880, disposition (in horizontal direction)of arm sections 302A and 302B in an endoscope image obtained through anobject lens of a viewing device (viewing unit) attached to the firstsheath 301 can be coincided with the disposition (in horizontaldirection) of the two operation units 530A and 530B. This improvescorrelation of an operator's perception and actual inner-body movement,thereby facilitating manipulation. Furthermore, less force is requiredfor an operator to operate only the operation sticks 531A and 531B andthe operation sections 506A and 506B of the procedure instruments 504Aand 504B. Dispositions having reverse correlation with respect tohorizontal or vertical direction provide similar operational perceptionobtained by laparoscopic instruments.

The configuration of the first operation unit 530A is explained.

As illustrated in FIGS. 2 to 4, the first operation unit 530A has abracket 551A fixed to the base 521. The bracket 551A is fixed so that anopening 552A is substantially orthogonal to the center line of the firstoperation unit 530A. A first rotation mechanism 561A is attached tohorizontal side surfaces of the bracket 551A. The first rotationmechanism 561A has a pair of support chips 562A and 563A that are fixedto place the opening 552A of the bracket 551A therebetween. A rotationshaft 564A is disposed to the support chip 562A. A rotation shaft 565Ais disposed to the support chip 563A. The rotation shafts 564A and 565 aare disposed coaxially. A frame 567A is supported by this pair ofrotation shafts 564A and 565 a so as to be freely capable of rotatingwith respect to the bracket 551. An opening of a rectangular frame 567Ais disposed orthogonal to the center line of the first operation unit530A. The operation stick 531A is inserted through the frame 567A. Theoperation stick 531A engaging with the frame 567A in rotating angles ofthe rotation shafts 564A and 565 a is inserted so as to be independentlycapable of tilting in the axial lines of the rotation shafts 564A and565A.

As illustrated in FIG. 5, the tip section 571A of the operation stick531A extends beyond the frame 567A. Ball rollers 572A are provided tothe tip section 571A. The ball rollers 572A are disposed to place thecenter line of the operation stick 531A therebetween. The line passingthrough the centers of two ball rollers 572A is parallel with the axiallines of the rotation shafts 564A and 565A of the first rotationmechanism 561A as illustrated, i.e., where the operation stick 531A isnot tilted. Distances Laa between the rotation shaft 564A and 565A andthe ball rollers 572A are, for example, 50 to 200 mm.

Frames 580A of the second rotation mechanism 581A are farther disposedso as to place the ball rollers 572A therebetween and slide on the ballrollers 572A. The frames 580A are supported rotatively by the pair ofrotation shafts 584A and 585A. The pair of the rotation shafts 584A and585A are disposed coaxially so that the axial lines are orthogonal to apair of rotation shafts 564A and 565A and also orthogonal to the centerline of the first operation unit 530A. The rotation shafts 584A and 585Aare supported by support chips 582A and 583A each fixed on a verticalside surface of the bracket 551A.

The configuration of the rotation shafts 584A and 585A of the secondrotation mechanism 581A will be explained here. Since the rotationshafts 584A and 585A have the same configuration, the rotation shaft584A will be explained herein for reference.

As illustrated in FIGS. 6 and 7, the rotation shaft 584A has a bearing591 fixed to the support chip 582A. The bearing 591 has a flange at anend of the cylinder so that the bearing 591 is fixed to the support chip582A by bolts passing through holes formed on the flange. Outer rings ofthe bearings 592 and 593 are press-fitted into the inside of thecylinder of the bearing 591 so as to be separate in the axial line. Adrive shaft 594 is supported by the bearings 592 and 593 rotativelyrelative to the bearing 591. The reduced diameter portion of the driveshaft 594 passes through the bearing 591.

An end section of the drive shaft 594 is enlarged in diametersubstantially to that of the bearing 591. A coil spring 596 is woundaround between an outer periphery of the drive shaft 594 and an outerperiphery of a cylindrical section of the bearing 591. Terminals 596Cand 596D are bent on both sides of the coil spring 596. A terminal 596Cis engaged with a groove formed on the flange 594C formed at an end ofthe drive shaft 594. An elemental wire of the coil spring 596 isrectangular in cross section. The rectangular shape may be a square or arectangle.

The drive shaft 594 is formed by a protrusion 594D and a flange 594C. Aplurality of screw holes are formed around the protrusion 594D. Eachrotative pin 597 is screwed into each screw hole disposed by 180 degreesoffset in a circumferential direction. An inner ring of the bearing 598is press-fitted and fixed into the protrusion 594D. A bearing 599 isattached to an outer periphery of the bearing 598. The bearing 599 has acylindrical section 599D having a flange. Inserted in advance into thecylindrical section 599D is a ring retainer 600 that depresses the ringretainer 600 toward a drive shaft 594 with a preload screw 602 via adiaphragm spring 601. A plurality of through-holes 599C are formed onthe flange of the bearing 599 at equal intervals in a circumferentialdirection. The through-holes 599C are disposed corresponding to thedisposition of the screw holes of the drive shaft 594. The diameter ofthe through-hole 599C is greater than that of a head portion of therotative pin 597. That is, the through-hole 599C has freeplay.

Provided further to cover the flange 594C of the bearing 594 and a coilspring 576 is a cylindrical cover 603. A notch 603C is formed on a baseportion of the cover 603. The other terminal 596D of the coil spring 596is hooked at the notch 603C. In addition, a cylindrical section 599D ofthe bearing 599 protruding from the cover 603 is fixed to the frames580A by a pin.

Since an initial state of the coil spring 596 tightens the outerperipheries of the drive shaft 594 and the bearing 591, the drive shaft594 is joined to the bearing 591 by the coil spring 596. Since thebearing 591 is fixed to the support chip 582A, the drive shaft 594cannot rotate in the direction for tightening the coil spring 596.However, it is rotatable in a direction for loosening the coil spring596. In contrast, a tilting movement provided by an operator of theoperation stick 531A into the direction for tightening the coil spring596 tilts the frames 580A that makes contact with the operation stick531A. Tilting the frames 580A rotates the bearing 594 of the rotationshaft 584A and the cover 603. Rotating the cover 603 loosens the coilspring 596, thereby releasing the drive shaft 594 locked to the bearing591. This results in allowing the drive shaft 594 to rotate, therebytransferring the rotation to a sprocket 595. The present symmetricdisposition of the rotation shaft 585A with respect to the operationstick 531A transfers the rotational movement of the operation stick 531Abut not the rotational movement for tightening the coil spring 596 fromthe sprocket 595. The operator's operation is transferred but a reactionforce by the sprocket 595 is maintained when the operator stops theoperation. Thus, the position is maintained, and the operation can befacilitated.

The coil spring 596 for use in such a spring clutch must be made from ahigh-hardness material. Use of a high-gravity material, e.g. iron, maycause an increase in the weight of the operation section 520. Therefore,a high-hardness and low-gravity material, e.g., duralumin (#2000) orextra super duralumin (#7000), may be used.

Meanwhile, loosening the coil spring 596 to release the locked state andtransferring the rotation via the coil spring 596 inevitably provide anexcessive force acting on the coil spring 596. In order to avoid such astate, a play is provided so that the head portion of the rotative pin597 of the drive shaft 594 makes contact with a periphery wall of thethrough-hole 599C of the bearing 594 after releasing the locked state.Rupture of the coil spring 596 is prevented by transferring the rotationby means of the rotative pin 597. The spring clutch having such aconfiguration is not limited to the present embodiment and can be usedfor a rotative structure for the procedure instrument or for theovertube.

In addition, a drive shaft 584 protruding from the flange of the bearing591 is supported by bearings 613 and 614 so as to be rotative withrespect to a hollow shaft 612. The sprocket 595 is fixed to a hollowshaft 611. It should be noted that a rotative member for pushing anddrawing a wire, e.g., a wire pulley, may be used in place of thesprocket 595.

The hollow shaft 612 is rotatively supported by the bearing 592 withrespect to the bearing 591. The drive shaft 594 and the hollow shaft 612both protruding over the sprocket 595 are inserted in a torque limiter611. The torque limiter 611 includes an outer 611C fixed to the hollowshaft 612 and an inner 611D fixed to the drive shaft 594. The inner 611Dand the outer 611C unitarily rotate until a predetermined torque isapplied. When excessive torque is applied, the outer 611C slides on theinner 611D; and thus, the rotation is not transferred.

As illustrated in FIG. 8 showing a configuration of the rotation shaft585A, the sprocket 595 is rotatively housed in a circular recessingsection 621 formed in the support chip 583A. A chain 622 is wound onteeth of the sprocket 595. A groove 623 is formed to the support chip583A. An end part of the chain 622 can be drawn into a groove 623 thatcontinues to the recessing section 621. The groove 623 is formed deeperthan the recessing section 621. Providing a gap 624 between the groove623 and the recessing section 621 prevents the chain 622 from beingentangled between the sprocket 595 and the recessing section 621, thusguiding the chain 622 into the groove 623.

A first bending wire 315A is fixed to an end part of the chain 622. Thefirst bending wire 315A bends the first bending parts 306 of the firstarm members 302A illustrated in FIG. 1 in a right-hand direction.

As illustrated in FIG. 8, the first bending wire 315A is drawn into anadjuster 641 disposed at an end part of the groove 623 of the supportchip 583A and introduced into a connection sheath 515 together with thecoil sheath passing through a coil sheath 642 connected to the adjuster641. The first bending wire 315A is finally reached to the first armmember 302A. As illustrated in FIGS. 8 and 9, the adjuster 641 has acoil base 651 fixed to the support chip 583A. A screw hole 651A isformed to the coil base 651. An adjustment shaft 652 having a thread onthe outer periphery thereof is screwed into the screw hole 651A. Theadjustment shaft 652 is a cylinder having a bottom. An end section 652Acorresponds to the bottom part into which a coil stopper 653 isinserted. The removal of the coil stopper 653 is prevented by engaging aflange-shaped protrusion 653A with an inner surface of the end section652A. Removal prevention in the reverse direction is provided byattaching a lock-screw 654 to the outer periphery. An end part of thecoil sheath is fixed to the coil stopper 653. The first bending wire315A passes through the adjustment shaft 652, followed by the coilstopper 653 and the coil sheath 642. The first bending wire 315Asometimes loosely extends during the step using the medical treatmentendoscope 501. In this case, inserting a fixture into a hole 652B of theadjustment shaft 652 and rotating them cause the coil sheath 642together with the adjustment shaft 652 to move in the axial direction.Forwarding the coil sheath 642 draws the first bending wire 315A fromthe coil sheath 642, thereby adjusting the loose state. Since the loosestate can be adjusted by means of a screw, it is not necessary todissemble the apparatus. Since the adjustment shaft 652 is rotativelyengaged with the coil stopper 653, rotating the adjustment shaft 652will never rotate the coil sheath 642.

Also, a sprocket 595 of the rotation shaft 584A is housed in the supportchip 582A, and the chain 622 is wound around the sprocket 595. Afirst-bending wire which is not shown in the drawing is attached to thechain 622. The first bending wire 315A bends the first bending parts 306of the first arm members 302A illustrated in FIG. 1 in a right-handdirection. An adjuster 641, also provided to the support chip 582A, canadjust the loose state by forwarding or drawing the coil sheath 642having the first bending wire 315B therethrough. The first bending wire315B inserted through the coil sheath 642 is introduced into theconnection sheath 515 together with the coil sheath 642 and reached tothe first arm member 302A.

As explained previously, the torque limiters 611 provided to therotation shafts 584A and 585A prevent the rotation of the rotation shaft585A from being transferred to the sprocket 595 when an excessive inputis provided from the operation stick 531A. This results in preventing anexcessive force from being applied to the first bending wire 315A.Considering a case assumed to use no torque limiter 611 may lead to apossibility where an excessive force is applied to the first bendingwire 315A. The torque limiter 611 for controlling the maximum torque canprevent the first bending wire 315A from being fractured. In addition,disposing the torque limiter 611, the sprocket 595, and the rotationshafts 564A and 565A in this order from the outside shorten the distancebetween the support chips 582 a and 583A, thereby downsizing the bracket551A. This increases freedom in layout and contributes to a downsizedand light-weight configuration.

The first rotation mechanism 561A will be explained next principallywith reference to FIG. 5.

A rotation shaft 564A has a similar configuration to the rotation shaft584A of the second rotation mechanism 581A except for the drive shaft594 attachably engaged with the frame 567A via the rotative pin 597 inthe rotative direction. Similarly, the other rotation shaft 565A has asimilar configuration to the rotation shaft 585A of the second rotationmechanism 581A except for the drive shaft 594 attachably engaged withthe frame 567A via the rotative pin 597 in the rotative direction.

Furthermore, a first bending wire 315D is joined to the sprocket 595 ofone of the rotation shafts 564A via the chain 622. A first bendingdownward-operating wire 315D is joined to the sprocket 595 of one of therotation shafts 564A via the chain 622. The first bending wire 315C andthe bending wire 315D bend two first bending parts 306 of the first armmembers 302A illustrated in FIG. 72 in vertical opening directions. Theadjuster 641, also provided to the support chip 562A and 563A, canadjust the loose state by forwarding or drawing the coil sheath 642having the first bending wires 315C and 315D therethrough.

Next, the operation stick 531A will be described.

In the operation stick 531A as illustrated in FIGS. 5, 6, and 10, threecylindrical shafts 701, 702, and 703 bundled together are fixed to a tipportion to which a ball roller 572A is attached. The central shaft 701is longer than two shafts, i.e., shafts 702 and 703. The other twoshafts 702 and 703 barely reach to an abutment section 710 that servesas a rotative fulcrum making contact with the frame 567A of the firstrotation mechanism 561A. In contrast, the central shaft 701 extendsbeyond an abutment section 710.

A second bending slider 711 capable of freely forwarding or retractingin the axial direction is attached to the central shaft 701.Furthermore, a ratchet base 712 is fixed to a base end of the shaft 701.In the initial state, the second bending slider 711 cannot be extendedor retracted because the second bending slider 711 is joined to theratchet base 712 by a connection plate 713 connected to the secondbending slider 711.

As illustrated in FIG. 11, a through-hole 712A is formed in the centerof the ratchet base 712. The through-hole 712A serves as an entrancefrom which the operation section 506A of the procedure instrument 504Ais inserted. Furthermore, a part 712B of an outer periphery of theratchet base 712 extends in a direction orthogonal to the axial linedirection. Putting a thumb here allows the second bending slider 711 tobe smoothly forwarded or retracted. A piston 715 slidable in a radialdirection is housed in the ratchet base 712. The piston 715 is urged bya coil spring 716 in a radial direction orthogonal to the axial linedirection. A protrusion 715A at the tip protrudes into a through-hole712A that is an insertion path for the procedure instrument 504A. A slit717 is formed on the piston 715. An engagement chip 717A is formed inthe slit 717. A first groove 718 of the connection plate 713 is engagedwith the engagement chip 717A. The first groove 718 is inserted througha slit 712C penetrating the ratchet base 712. Meanwhile, a verticalgroove 717C that is parallel in a radial direction may be formed on thepiston 715 as illustrated in FIG. 12. Inserting the tip portion of aclamping-bolt 716A (see FIG. 10) into a vertical groove 717C of an outerperiphery of the ratchet base 712 can prevent the rotation of the piston715. This prevents the piston 715 from galling the connection plate 713,thereby providing smooth movements of the piston 715 and the connectionplate 713 as explained later.

The tip of the connection plate 713 is joined to the second bendingslider 711 by a fulcrum pin 721 and extends substantially parallel inthe axial line from here toward the ratchet base 712. The recessingshape of the first groove 718 allows the engagement chip 717A of thepiston 715 to enter there, and a midpoint of the wall surface of the tipportion of the first groove 718 forms an inclination surface 718A. Theinclination surface 718A gradually widens the first groove 718 from themidpoint to the tip portion. A second groove 719 is formed at a furthertip portion than the first groove 718 is formed. The recessing shape ofthe second groove 719 allows the engagement chip 717A of the piston 715to enter there. The second groove 719 is deeper than the first groove718. The base end wall surface of the second groove 719 forms aninclination surface 719A. The inclination surface 719A gradually widensthe second groove 719 toward the tip portion. The first groove 718 ispositioned so that the second bending part 308 of the first arm member302A as illustrated in FIG. 1 becomes straightened. The second groove719 is positioned so that the second bending parts 308 bend to open thefirst arm member 302A. This allows the arm section 302A to close byengaging the first groove 718 with the piston 715, and allows a secondarm member 303A to open by engaging the second groove 719 with thepiston 715. As previously described, the engagement of the piston 715with the grooves 718 and 719 can be released with a small force sincethe inclination surfaces 718A and 719A are formed in the grooves 718 and719. This facilitates smooth switching of the engagement position of thepiston 715 with the grooves 718 and 719. As illustrated in FIG. 23, aspring 791 forces the second bending slider 711 and the connection plate713 to be positioned toward the tip portion by the spring force when theprocedure instrument 504A is not inserted and thus, the first groove 718engages with the piston 715. As illustrated in FIG. 25, the piston 715is pushed by the operation section 506A of the procedure instrument 504Awhen the procedure instrument 504A is inserted. Since this state of theengagement chip 717A can move up the inclination surface 718A, thesecond bending slider 711 can be drawn, and the second bending part 308can be opened. In this configuration, the procedure instrument 504A mustbe inserted to draw the second bending slider 711 because the tip of theprocedure instrument 504A can hardly be passed through the opening stateof the second bending part 308. As illustrated in FIG. 27, theengagement chip 717A makes contact with the inclination surface 719A aslong as the second bending slider 711 is drawn toward the base end. Thetension applied by second bending wires 316A and 316B urges the slider711 toward the tip. As illustrated in FIGS. 28 and 29, raising thepiston 715 necessitates a significant force if the disposition angle ofthe inclination surface 719A is significantly equal to 90°. If thedisposition angle is substantially horizontal, the piston 715 isspontaneously raised by the tension applied by the second bending wires316A and 316B and therefore, the second bending slider 711 moves towardthe tip, and the second bending part 308 closes. The suitable angle α ofthe inclination surface 719 is 60°≦α<90°.

The second bending slider 711 is disposed coaxially with the axial lineof the operation stick 531A. Therefore, the compact first operation unit530A can be obtained. Formed at the base end thereof is an edge section711A for putting a thumb. A linear stroke 722 is built in a portionmaking contact with the shaft 701 to provide smooth sliding movement onthe shaft 701.

As illustrated in FIG. 13, two pipes 731 are attached to the tip of thesecond bending slider 711 so as to place the axial line between pipes731. Second bending wires 316A and 316B are passed respectively throughthese pipes 731. The second bending wires 316A and 316B are fixed to anengagement member 732 in the second bending slider 711 so that thesecond bending wires 316A and 316B cannot be removed from the secondbending slider 711. Disposing the second bending wires 316A and 316Bsymmetrically with respect to the second bending slider 711 equalizesthe force applied to the second bending slider 711 and thus providingsmooth movement thereof.

Two shafts 702 and 703, disposed further toward the tip, each have thepipe 731 inserted therethrough. The pipe 731 and the second bendingwires 316A and 316B are inserted through the shafts 702 and 703 disposedside by side. The shafts 702 and 703 each have a retainer member 741 atthe base end. Another pipe 742 is inserted from the tip through theretainer member 741. A pipe 731 and a second bending-wires 316A and 316Bare passed through the pipe 742. The tip of the pipe 742 is supported bya coil-receiving casing 743. The coil-receiving casing 743 is screwed inthe hole of a cylindrical pusher 744 and fixed there. An end portion ofa coil spring 745 makes contact with the base end of the pusher 744. Theother end portion of the coil spring 745 is butted against the retainermember 741. The pusher 744 is urged by the coil spring 745 toward thetip. In response to excessive force that draws the second bending wires316A and 316B, a force that relatively moves a coil sheath 747 to anoperator's hand is applied and thus, the coil spring 745 is compressedvia the pusher 744. The coil spring 745 that is preset to a lengthexerting a predetermined force begins to contract if the preset force isoverreached. Since the second bending wires 316A and 316B can further bedrawn in accordance with the contraction of the coil spring 745, anexcessive force is not applied to the second bending wires 316A and316B. A force applied to the second bending wires 316A and 316B willnever increase rapidly as long as the coil spring 745 can be contractedif an excessive force is applied and therefore, the second bending wires316A and 316B will never be cut since overload mass is curbed.Meanwhile, the coil spring 745 is compressed by a pusher retainer 746screwed from the tips of the shafts 702 and 703. Since the initialposition of the pusher 744 can be adjusted in accordance with thecompression mass of the pusher retainer 746, differences in rigidity andbending force based on the coil springs 745 can be adjusted.

Furthermore, only the second bending wires 316A and 316B are extractedfrom the pipe 742. The second bending wires 316A and 316B are insertedthrough the pusher retainer 746 in the coil-receiving casing 743 andintroduced through the connection sheath 515 together with the coilsheath 747 to reach to the second bending part 308. The base end of thecoil sheath 747 is brazed to a tubular coil receiver 748 and fixed therein the coil-receiving casing 743. A coil-receiver-retainer 749 isscrewed from the tip through the coil-receiving casing 743. Thecoil-receiver-retainer 749 rotatively locking the coil receiver 748prevents the coil sheath 747 from being removed from the coil-receivingcasing 743, thereby preventing the pusher retainer 746 from beingtwisted. The lengths of the second bending wires 316A and 316Bcorresponding to the coil sheath 747 may sometimes have an assemblyerror, and such an error may sometimes be caused by the stretching ofthe second bending wires 316A and 316B. Adjusting the screwing amount ofthe coil-receiving casing 743 relative to the pusher 744 can correct theerror.

As illustrated in FIGS. 13 and 14, a channel 801 for passing a procedureinstrument 504A therethrough is built in the central shaft 701. Thechannel 801 has, in order from the base end, a retainer 802 thataccommodates the procedure instrument 504A, a coil spring 803 insertedbetween the retainer 802 and the tip section 571A, and an extendablepipe 804 disposed in the coil spring 803. A hole 802A is formed in thecenter of the retainer 802. The hole 802A serves as an entrance forinserting the procedure instrument 504A therefrom. The hole 802A is atapered hole where the opening diameter increases toward the base end.The hole 802A having a funnel shape facilitates the insertion of adistal end of an insertion section 507A of the procedure instrument504A. The extendable pipe 804 has three pipes 805, 806, and 807 each ofwhich are different in diameter. These pipes are disposed coaxially. Aremoval stop 808 is attached to the pipes 805 and 806. A stopper 809locked to the removal stop 808 is attached to each pipe 806 and 807.That is, the extendable pipe 804 becomes the shortest when three pipes805, 806, and 807 substantially overlap. Extending each pipe 805, 806,and 807 and locking the stopper 809 to the removal stop 808 allows theextendable pipe 804 to be the longest. While the drawings illustrate thecompressed state of the coil spring 803, the coil spring 803 restoresunder the no-load condition. The retainer 802 moves to the vicinity of ashaft 701 and to the vicinity of the distal end of the piston 715. Sincethe retainer 802 is disposed at the base end of the shaft 701 unless theprocedure instrument 504A is not inserted, the insertion section 507A ofthe procedure instrument 504A can be inserted easily. The retainer 802is pushed by the tip portion of the operation section 506A of theprocedure instrument 504A to be forwarded to the position illustrated inFIG. 13 when the procedure instrument 504A is inserted. It should benoted that the extendable pipe 807 is not limited to a triple-pipestructure.

A space for passing the procedure instrument 504A therethrough isprovided in a tip section 571A that joins three shafts 701, 702, and703. An airtight valve 811 is provided on a path into which theprocedure instrument 504A is inserted and thus, the airtight conditioninside of the body subjected to a medical operation can be maintainedeven if the procedure instrument 504A is removed during the medicaloperation. The airtight valve 811 is made of, for example, a rubbersheet disposed to seal a hole 571B that communicates with the shaft 701.Formed to the rubber sheet is a notch into which an insertion portion ofthe procedure instrument 504A can be inserted. Passing the procedureinstrument 504A therethrough necessitates opening the notch. Removingthe procedure instrument 504A closes the notch, thereby maintaining theairtight condition. A retainer 812 is used to fix the airtight valve811. Fixing the retainer 812 onto the tip section 571A by screwsfacilitates exchanging the airtight valve 811 made of a rubber sheet.Meanwhile, the procedure instrument 504A is introduced into the bodythrough a hole 812A formed in the retainer 812. Forming a hole 812A soas to be tapered toward the tip facilitates the insertion of theprocedure instrument 504A.

The configuration of the second operation unit 530B is explained.

The second operation unit 530B has a symmetric configuration to thefirst operation unit 530A with respect to the horizontal center line ofthe operation section 520. A symbol “B” is added to some componentsincluded in the operation unit 530B to distinguish them from those ofthe first operation unit 530A.

A procedure instrument 504A inserted through the operation section 520will be explained next. Although only the procedure instrument 504A willbe explained here, it should be noted that the procedure instrument 504Bhas the same configuration. An end of each procedure instrument 504A and504B may be a high-frequency knife, a puncture needle, a snare, a clip,or additional forceps.

As illustrated in FIG. 15, a treatment section 505A (see FIG. 1) and anoperation section 506A both provided to the tip of the procedureinstrument 504A are joined by an elongated flexible insertion section507A. The operation section 506A has a main body section 911 having acam 910 at the tip thereof. A slider 912 that drives the treatmentsection 505A is attached at the base end of the main body section 911rotatively in the axial line direction. In addition, a finger-hook ring913 is attached to the base end of the main body section 911.

As illustrated in FIG. 16, a ring 913 is joined to the main body section911 via an E ring 915. Operability is desirable since the ring 913 canbe rotated by the E ring 915 around the axial line. It should be notedthat a rubber-made protection member 916 may be used to be fitted to theinside of the ring 913 as illustrated in FIGS. 88 and 89. A groove 916Adetachable from the ring 913 is formed on an outer periphery of theprotection member 916. The use of rubber eases pain on fingers duringoperation. In addition, a detachable configuration is superior inmaintaining cleanliness and sterilization. Making the protection member916 of for example, a silicone rubber, imparts chemical resistance andsterilization.

As illustrated in FIGS. 5 and 15, the tip portion of the cam 910 is ataper where an opening diameter decreases. When a taper surface 910A isinserted through the operation stick 531A, the taper surface 910A servesfor pushing up the piston 715 and pressing the channel 801. The outerdiameter of the cam 910 is substantially the same as the inner diameterof the shaft 701 so that the cam 910 is slidable on the shaft 701. Fourblade sections 921 extending in the axial line direction are provided tothe base end of the cam 910. As illustrated in FIG. 19A, each bladesection 921 is provided only on the outer periphery of the cam 910. Aside surface 921A in the circumferential direction forms a tilted andcurved surface from the center toward radially outward.

In addition, as illustrated in FIGS. 19B and 20, a slope 921C directedto the tip together with a gap surface 921B standing in a radialdirection may be formed on the outer periphery of the tilted sidesurface 921A of the cam 910. A gap 921D between the tilted side surface921A and the outer periphery of the cam 910 is smoothly resolved by theslope 921C. A side surface 921E disposed opposite to the side surface921A in the blade section 921 has a space greater than the diameter ofthe piston 715 between the side surface 921A of another blade section921 adjacent in the circumferential direction and the side surface 921E.The side surface 921E is tilted in the direction the same as the tiltingdirection of the side surface 921A. The tilting direction of the sidesurface 921E is significant, i.e., forms a steep surface.

A main body section 911 is screwed into an inner hole of the cam 910 andfixed there. The outer diameter of the main body section 911 including apart inserted into the cam 910 and a stopper 922 having an increaseddiameter may be reduced gradually toward the base end. That is, FIG. 15shows an example in which a diameter d2 at the base end is smaller thanthe diameter d1 at the tip. An operation section 506A of the hole 571Bhas a play relative to the operation stick 531A to prevent the main bodysection 911 from pushing up the piston 715 even if the operation section506A is tilted or bent. Also, the tip of the piston 715 protruding intothe shaft 701 is configured to have a correlation with the second groove719 so that a space is formed between the piston 715 and the secondgroove 719. Thus, the piston 715 is prevented from interfering with themain body section 911 and therefore, the forward movement or retractingmovement of the procedure instrument 504A can be smooth. In addition,the stopper 922 makes contact with a ratchet base 712 when the procedureinstrument 504A is inserted through the operation stick 531A andregulates the procedure instrument 504A to prevent it from being pushedfurther.

As illustrated in FIG. 21, a pipe 931 is fixed to a slider 912. Anoperation wire 932 for driving the treatment section 505A is passedthrough the pipe 931. The base end of the operation wire 932 and thebase end of the pipe 931 are locked to the slider 912 by an engagementmember 933. The pipe 931 passing through a slit 911A of the main bodysection 911 is extendably supported by a resin-made pipe retainer 934.An operation wire 932 passing through another pipe 935 fixed to the piperetainer 934 is extracted and enters an intermediate coupling 941together with the pipe 935, and is inserted into a metal-madesingle-layered coil 942 therein. Isolation is imparted to the pipe 935by coating it with a thermally-contracting tube.

As illustrated in FIG. 22, a coil receiver 943, to which the base end ofthe single-layered coil 942 is fixed, is housed in the base end of theintermediate coupling 941. The tip of the previously described pipe 935is inserted into the coil receiver 943. A diameter-contracting section941A is provided to the intermediate coupling 941 to prevent the coilreceiver 943 from being removed toward the tip. The single-layered coil942 is inserted into a multi-layered coil 951 farther toward the tipthan the diameter-contracting section 941A. The multi-layered coil 951is configured to have more than three coils disposed coaxially. Forexample, an innermost layer coil and an outermost layer coil are woundin the same direction, and an intermediate-layer coil is wound in theopposite direction in the case of a three layer structure. This resultsin that rotating of the innermost layer coil and the outermost layercoil in the coil-loosening direction tightens the intermediate-layercoil, thereby causing the intermediate layer coil to interfere with theinnermost layer coil. Thus, the rotation torque is transferred to thetreatment section 505A at the tip. Rotating in the opposite directioncauses the loosening intermediate layer coil to interfere with theoutermost layer coil, thereby transferring the rotation torque to thetreatment section 505A. In addition, using a metal-made multi-layeredcoil 951 improves the transferred rotation torque. A resin-made coil maybe used for obtaining insulation.

A coil receiver 952 is brazed to the multi-layered coil 951. The coilreceiver 952 is slidably inserted through a longitudinal groove 941Bformed on the insulative intermediate coupling 941. Accordingly themulti-layered coil 951 can engage with the intermediate coupling 941 inthe rotative direction, but not in the forward direction or theretracting direction. Meanwhile, a resin-made removal stop 953 isattached to the tip of the intermediate coupling 941. Since the removalstop 953 regulates the protrusion of the coil receiver 952, themulti-layered coil 951 will never be removed from the intermediatecoupling 941. Also, the coil receiver 952 will never make contact withthe main body section 911. This configuration will not affect the lengthof the multi-layered coil 951 even if the single-layered coil 942contracts or extends during a medical operation.

Also, the single-layered coil 942 can be brazed to the coil receiver 943that is slid toward the base end and extracted from the intermediatecoupling 941 after brazing the multi-layered coil 951 to the coilreceiver 952. Meanwhile, the intermediate coupling 941 should preferablybe made of high heat-resistance resin, e.g., PEEK (polyetheretherketone)taking the high temperature applied during the brazing operation intoaccount.

The outer periphery of the multi-layered coil 951 extracted from theintermediate coupling 941 is coated by an insulative tube 954. A fluororesin-made insulative tube 954 has lower sliding friction, thusproviding desirable rotation. The isolated and coated multi-layered coil951 passing through a winding-protection pipe 955 is extracted from ahole 910C formed at the tip of the cam 910.

The main body section 911 should preferably be made of a metal materialtaking durability into account. In this case, providing insulation tothe operation section 506A realizes a procedure instrument 504A for usein a medical operation with a high-frequency apparatus. Therefore, theuse of a resin in the removal stop 953, intermediate coupling 941,thermally-contracting tube of the pipe 935, pipe retainer 934, andslider 912 reliably isolates the main body section 911 from theoperation wire 932 and coils 942 and 951. This results in usinghigh-frequency waves with the procedure instrument 504A such as anincision knife or high-frequency forceps. Apparatuses of this type canbe used compatibly. Insulation coating onto the multi-layered coil 951may not be necessary unless the procedure instrument is of a highfrequency application-type apparatus. In this case, increasing thethickness of the multi-layered coil 951 corresponding to the thicknessof the thermally contracting tube for use as a coating will provide amore rotative procedure instrument. The thickness of the thermallycontracting tube utilized for the single-layered coil 942 will providesignificantly more resistance against compression or expansion.

Consequently, steps for carrying out operations using the medicaltreatment endoscope 501 will be explained. Meanwhile, a case will beexplained as follows where an endoscope is introduced from a mouth as anatural orifice of a patient, a procedure instrument is introduced froman opening formed in a stomach into an abdominal cavity to grasp tissue.It should be noted that operations can be carried out through anotherorgan or another path. Although we concentrate on the procedureinstrument 504A and the first operation unit 530A in the explanation,the procedure instrument 504B and the operation unit 530B can be usedindependently because they are mere symmetric components.

Two procedure instruments 504A and 503B are inserted into the medicaltreatment endoscope 501. The procedure instrument 504A is inserted intothe first operation unit 530A. As schematically illustrated in FIG. 23,when the procedure instrument 504A is not inserted yet, the piston 715provided to the ratchet base 712 at the tip of the first operation stick531A engages with the first groove 718 of the connection plate 713 andlocks the connection plate 713. Locking the connection plate 713prevents the second bending slider 711 from moving since the ratchetbase 712 is unmovable. This corresponds to a position where the secondbending part 308 becomes straightened. That is, the second bending part308 is always straightened in the medical treatment endoscope 501 whenthe procedure instrument 504A is inserted. As illustrated in FIG. 24,forwarding the operation section 50A into the first operation stick 531Apushes up the piston 715 with the taper surface 910A of the cam 910 atthe tip of the operation section 506A. As illustrated in FIG. 25, thepiston 715 being capable of moving up the inclination surface 718A ofthe first groove 718 of the connection plate 713 allows the secondbending slider 711 to be controlled in the direction indicated by anarrow shown in the drawing.

As illustrated in FIG. 5, the insertion section 507A of the procedureinstrument 504A passing through the channel 801 is introduced into achannel in the connection sheath 515. The insertion section 57A furtherpassing through the endoscope insertion section 503 is introduced to thetip of the first arm member 302A. Similarly, the procedure instrument504B inserted into the operation stick 531B of the operation unit 530Bis disposed at the tip of the second arm member 303A.

After closing the arm sections 302A and 303A having the procedureinstruments 504A and 504B previously passing therethrough, the endoscopeinsertion section 503 is introduced into a body cavity from an openingpreviously formed in a stomach wall. In addition, the endoscopeinsertion section 503 may be passed through an overtube previouslyinserted into a body.

A section to be treated is confirmed while observing with a monitor animage obtained by an endoscopic image-pickup device provided to the tipof the endoscope insertion section 503. At this time, a first operatormanipulates an angle knob 512 of the endoscope insertion section 502 andbends a third bending part 203B. Furthermore, a second operator bendsthe second bending part 308 and the first bending part 306 if necessary.

Bending the second bending part 308 necessitates retracting the secondbending slider 711 provided to the operation sticks 531A and 531B. Asillustrated in FIG. 25, retracting the second bending slider while thepiston 715 is elevated causes the engagement chip 717A of the piston 715to go up the inclination surface 718A, thereby causing the connectionplate 713 to slide on the piston 715 as illustrated in FIG. 26. Thesecond bending slider 711 which cannot be farther retracted after thepiston 715 is housed in the second groove 719 as illustrated in FIG. 27.The second bending part 308 as illustrated in FIG. 1 bends at thisposition, causing the first arm member 302A to open. In addition, sincethe second groove 719 is shallower than the first groove 718, a space Ssis formed between the cam 910 and the main body section 911 of theoperation section 506A when the piston 715 engages with the secondgroove 719. Absence of sliding friction between the main body section911 and the piston 715 allows smooth extension and retraction of themain body section 911.

Furthermore, bending the first bending part 306 necessitates tilting theoperation sections 506A and 506B of the procedure instruments 504A and504B while observing the endoscopic image.

As illustrated in FIG. 4, tilting the operation section 506A upwardrelative to the operator causes the rotation shafts 564A and 565A of thefirst rotation mechanism 561A to rotate in accordance with the tiltingangle. The rotation of the sprocket 595 attached to the rotation shafts546A and 565 a causes extension and retraction of the first bendingwires 315A and 315B attached to the chain 622, thereby bending the firstbending part 306 upward. In contrast, tilting the operation section 506Adownward relative to the operator causes the rotation shafts 564A and565A of the first rotation mechanism 561A to rotate in the directionreverse to the upward tilting direction in accordance with the tiltingangle. The reverse rotation of the sprocket 595 attached to the rotationshafts 546A and 565 a causes extension and retraction of the firstbending wires 315A and 315B attached to the chain 622, thereby bendingthe first bending part 306 downward.

Tilting the operation section 506A in a right-hand direction relative tothe operator causes the rotation shafts 584A and 585A of the secondrotation mechanism 581A to rotate in accordance with the tilting angle.The rotation of the sprocket 595 attached to the rotation shafts 584Aand 585A causes extension and retraction of the first bending wires 315Cand 315D attached to the chain 622, thereby bending the first bendingpart 306 in the right-hand direction. In contrast, tilting the operationsection 506A in a left-hand direction relative to the operator causesthe rotation shafts 584A and 585A of the second rotation mechanism 581Ato rotate in the reverse direction in accordance with the tilting angle.The rotation of the sprocket 595 attached to the rotation shafts 584Aand 585A causes extension and retraction of the first bending wires 315Cand 315D attached to the chain 622, thereby bending the first bendingpart 306 in the right-hand direction.

Since the second rotation mechanism 581A is not driven when the firstrotation mechanism 561A is driven, and the first rotation mechanism 561Ais not driven when the second rotation mechanism 581A is driven, eachbending can be obtained without being affected by these rotationmechanisms. Meanwhile, tilting the operation section 506A drives thefirst and second rotation mechanisms 561A and 581A in accordance withthe tilting ratio with respect to the vertical and horizontaldirections, thereby bending the first bending part 306 diagonally in adirection the same as the tilting direction of the operation section506A. Since the center or barycenter of the operation stick 531A in thelongitudinal direction is configured to substantially coincide with thepositions of the rotation shafts 546A, 565A, 584A, and 585A, theoperation stick 531A and the operation section 506A of the procedureinstrument 504A during hands-free operation by the operator will notdescend with gravity; therefore, erroneous operation can be prevented.

A necessary force is optimized to operate the first bending part 306 bymeans of a non-electric wire-assisted operation. To be more specific, aportion of the operation stick 531A operated by the operator who inputsa force is decelerated by separating and offsetting the portion from therotation shafts 546A, 565A, 584A, and 585A. As illustrated in FIG. 6,since a deceleration ratio corresponding to a ratio between a distanceLr an a radius Rs of the sprocket 595 is obtained, the bending operationcan be carried out with a small force while downsizing the operationsection 520. In this case the distance Lr indicates the length betweenthe base end section of the operation section 506A of the procedureinstrument 504A. In addition, the deceleration enhances resolution,thereby enabling accurate bending operation.

As illustrated in FIGS. 5 and 6, since the point of the second rotationmechanism 581A to which a force is transmitted from the first operationstick 531A is offset toward the tip relative to the rotation shafts 564Aand 565A such as a roller bearing 572A as illustrated in FIG. 6, theforce necessary at the transfer position is decreased, and frictionamong components can be reduced. This decreases the rigidity requiredfor components used there and obtains a small and light-weight operationsection 520. Also, the use of the ball roller 572A at the point of thesecond rotation mechanism 581A to which the force is transferred fromthe first operation stick 531A reduces the friction due to the secondrotation mechanism 581A when rotating the first operation stick 531Avertically, thereby reducing the necessary force for the verticaloperation.

Grasping tissue necessitates adjusting the position of a forceps memberthat is opened or closed by the operation section 506A of the procedureinstrument 504A. For example, pushing the operation section 506A intothe first operation stick 531A causes the treatment section 505A toprotrude further from the first arm member 302A. Also, retracting theoperation section 506A from the first operation stick 531A causes thetreatment section 505A to be retracted into the first arm member 302A.As illustrated in FIG. 28, since this state of the cam 910 is hooked onthe piston 715, the procedure instrument 504A will not be undesirablyremoved from the first operation stick 531A.

Adjusting the direction of the procedure instrument 504A around theaxial line necessitates the main body section 911 of the operationsection 506A to rotate around the axial line. Thus, rotational torque isinput into the multi-layered coil 951 that is engaged to theintermediate coupling 941 in the rotational direction as illustrated inFIGS. 21 and 22. In the multi-layered coil 951, two coils adjacent toeach other in a radial direction interfere with each other while theyare tightened or loosened based on their combination of the windingdirection and the rotational direction of the operation section 506A andthus, rotational torque is transferred. Since the treatment section 505Ais fixed to the tip of the multi-layered coil 951, the transferredrotational torque rotates the treatment section 505A around the axialline. The rotation in the vicinity of the operator's hand is stoppedafter confirming that a desirable direction is obtained by means of anendoscopic image.

The slider 912 is forwarded after adjusting the direction and positionof the treatment section 505A. The operation wire 932 moves anopening-and-closing mechanism of the treatment section 505A to open apair of forceps members. The single-layered coil 942 receives anextension force generated by pushing the operation wire 932. Theextension force is not applied to the multi-layered coil 951 because themulti-layered coil 951 is not engaged with the operation section 506A inthe extension and retraction directions. This allows the treatmentsection 505A to be adjusted even if the forceps members are opened.Consequently, retracting the slider 912 causes the forceps members toclose and grasp tissue. The compression force generated temporarily isreceived by the single-layered coil 942.

The procedure instruments 504A and 504B are retracted from the medicaltreatment endoscope 501 after completing necessary treatments. Theprocedure instruments 504A and 505B are also retracted from the medicaltreatment endoscope 501 in order to exchange procedure instrumentsnecessary for a treatment. As illustrated in FIG. 28, the operationsection 506A is rotated around the axial line after the cam 910 abutsthe piston 715. The piston 715 is pushed up along the tilted sidesurface 921A of the blade section 921 of the cam 910. As illustrated inFIG. 29, providing the tilted side surface 921A enables pushing up ofthe piston 715 with a small force. Meanwhile, as illustrated in FIGS. 19and 20, the procedure instrument 504A will never be rotated excessivelyif the gap surface 921B is provided. Furthermore, providing the slope921C facilitates offsetting the piston 715 from the cam 910 in an axialline direction (thrust direction), thereby removal is easy. Meanwhile,it is preferable that the entire cam 910 be made of a metal in view ofbreakage protection. In addition, the cam 910 may be made of POM(polyoxymethylene) that has desirable slidability in view offacilitating operation in extension and retraction operations in thefirst operation stick 531A.

However, the treatment sections 505A and 505B cannot be removed if thesecond bending part 308 of the arm sections 302A and 303A is opened, andthe engagement of the piston 715 and the cam 910 can be released. Thepiston 715 pushed up by the cam 910 in the operation section 520 isconfigured to automatically restore the second bending part 308 to astraightened state. That is, pushing up the piston 715 and releasing theengagement with the second groove 719 retract the second bending slider711 with tension applied by the second bending wires 316A and 316B and aresilience of the coil spring 745. This results in causing the secondbending part 308 to restore into the straightened state. In addition, aresilient part like a spring 792 as illustrated in FIG. 13 may be addedto prevent energetic restoration of the second bending slider 711.Consequently, the medical treatment endoscope 501 is removed from thebody after removing the procedure instrument 504A.

Next, a modified example of the present embodiment will be described asfollows.

As illustrated in FIG. 30, operation sections 1001A and 1001B each foroperating the second bending slider 711 may be fixed to the bracket 551Aand a bracket 551B in parallel with each axial line of the operationsticks 531A and 531B. The operation sections 1001A and 1001B each havean extendable and retractable slider. Moving the slider causes the wirein a coil sheath 1002 to be extended or retracted. As illustrated inFIG. 31, the coil sheath 1002 is fixed to the coil receiver 1003attached to the ratchet base 712. A pipe 1004 is passed through the coilreceiver 1003. The pipe 1003 passing through the coil sheath 1002 isrotatively engaged with the second bending slider 711 via the wirereceiver 1005 together with the second bending wires 316A, 316B. A wire1006 joined to the sliders of the operation sections 1001A and 1001B ispassed through the pipe 1004. Retracting the sliders of the operationsections 1001A and 1001B moves the wire 1006, thereby drawing the secondbending slider 711 and opening the second bending part 308. In thisconfiguration, the operation section 520 can be downsized and thus,operation of the second bending part 308 can be facilitated. Also, thisconfiguration prevents the movement of the operation sticks 531A and531B during the operation of the second bending part 308. Thus, graspedtissue will never be moved unexpectedly.

As illustrated in FIG. 32, the base end of the cam 910 may be aninclination surface 1010. Drawing the procedure instrument 504A from thefirst operation stick 531A causes the piston 715 to move up theinclination surface 1010, thereby removing the procedure instrument504A. The procedure instrument 504A cannot be removed with a force basedon the retraction of the procedure instrument 504A toward the operatorduring a treatment. Further additional force will provide retraction. Inthis configuration, the procedure instrument 504A can be removed withoutrotating the operation section 506A.

In addition, operations for significant rotations of the procedureinstruments 504A and 504B will be explained with reference to FIGS. 33and 34. This includes cases where we intend to adjust the treatmentsection 505A in the optimum direction to grasp tissue. As illustrated inFIG. 33, the slider 912 is held with an index finger and a middlefinger. The hand-held state of the slider 912 is rotated in a clockwisedirection by 90°. The index finger and the middle finger are withdrawnfrom the slider 912 after rotating the slider 912 and the main bodysection 911 to the positions illustrated in FIG. 34. The hand notholding the slider 912 is rotated in a counterclockwise direction by 90°to the position illustrated in FIG. 33. This state of the insertionsection 507A of the procedure instrument 504A has friction relative tochannels in a first operation stick 531A and the second arm member 302A.To be more specific, the channels are a channel 801, a channel in theconnection sheath 515, and a channel in the endoscope insertion section503. Therefore, the insertion section 507A will not rotate in thecounterclockwise direction with a mere touch with the slider 912 andthus, its disposition is maintained. Repeating the above steps enables90° feed operation of the procedure instrument 504A.

As illustrated in FIG. 35, the medical treatment endoscope 501 may bepassed through the overtube 90. The first operator handling theendoscope insertion section 502 conducts ordinary endoscopic operationwith his/her left hand while operating the endoscope insertion section503 and overtube 90 with his/her right hand. The use of bending of theovertube 90 improves the approachability to the object position in theabdominal cavity.

Second Embodiment

In a medical treatment endoscope of the present embodiment, a channelfor inserting a procedure instrument therethrough is detachable in theoperation section.

As illustrated in FIG. 36, a medical treatment endoscope 1300 accordingto the present embodiment is provided with the endoscope insertionsection 502, the endoscope insertion section 503, and the operationsection 1102 that are the same as those of the first embodiment. Wiresfor maneuvering the two arm sections 302A and 302B extending from theendoscope insertion section 503 passing through the connection sheath515 are connected to a wire unit detachable from the operation section1350. Three wire units are provided to each arm section and include twofirst wire units having a vertically moving first wire unit 1301 and ahorizontally moving second wire unit 1302; and a second-bending-wireunit 1303. Therefore, the present embodiment is provided with six wireunits in total, i.e. wire units 1301A, 1302A, and 1303A that areconnected to the first arm section 302A and wire units 1301B (not shownin the drawing), 1302B, and 1303B that are connected to the second armsection 302B.

The operation section 1350 having substantially the same structure asthe operation section 520 of the first embodiment includes a firstoperation unit 1350A for maneuvering the first arm section 302A; and asecond operation unit 1350B for maneuvering the second arm section 302B.

The first wire units 1301A and 1301B are attached to first rotationmechanisms 1351A and 1351B of the operation units 1350A and 1350B, notshown in the drawing, respectively. The second wire units 1302A and1302B are respectively attached to second rotation mechanisms 1352A and1352B of each operation unit, not shown in the drawing. In the operationunits 1350A and 1350B, the second bending wire units 1303A and 1303B areattached detachably to second bending-operation-mechanisms 1353A and1353B, not shown in the drawing, provided between the first rotationmechanism and the second rotation mechanism.

The second-bending-operation mechanisms 1353A and [B]1353B are connectedto sliders 1355A and 1355B provided to operation sticks 1354A and 1354Bhaving procedure instruments inserted through the arm sections 302A and302B via transmission members, e.g. a wire. (details thereof will beexplained later). Drawing the sliders 1355A and 1355B proximally causesthe second bending 308 of the arm section to bend. Finger hook sections1356 formed by bending a plate member are provided to the sliders 1355Aand 1355B so that operation while grasping the operation sticks 1354Aand 1354B by hooking fingers thereto can be conducted.

Accordingly, maneuvering the operation sticks 1354A and 1354B cause thewires connected to the wire units 1301 and 1302 via rotation mechanisms1351 and 1352 to be operated, thereby permitting operation of the armsections 302A and 302B.

An operation stick (hereinafter called simply a “stick”) and thestructure of a channel will be explained next. It should be noted thatthe sticks 1354A and 1354B have the same structure in the followingexplanation provided in associate with the stick 1354A as an example.

FIG. 37 is a perspective view showing the stick 1354A. It should benoted that FIG. 37 is a perspective view facilitating visualization ofthe inside of the stick 1354A. The stick 1354A is provided with atubular main body 1357; a slider section 1358 having a slider 1355,provided therein, which will be explained later; and a fixture section1359 for fixing a channel unit 1360 to the main body 1357. The channelunit 1360 having a procedure instrument therethrough is inserted in themain body 1357 from the vicinity of the fixture section 1359 and isfixed to the fixture section 1359 detachably.

FIG. 38 is a perspective view showing the channel unit 1360 removed fromthe stick 1354A. The channel unit 1360 is provided with a tubular mainbody 1361; a connecting section 1362 attached to one of the ends of themain body 1361; and a mating fixed section 1363 fixed to the fixturesection 1359 of the stick 1354A.

The channel unit 1360 is made from a material resistible to cleaning andsterilization. Specific adaptable examples are: SUS303 and SUS 304 as ametal material; and, for example, polyester, polyetheretherketone, andpolyethersulphone as a resin material.

The connecting section 1362 is connected with the instrument channelwhich communicates with an inner cavity of the first arm section 302Aand extends to the connection sheath 515 through the endoscope insertionsection 503. It is preferable that the tip of the connecting section1362 is made from a flexible material which can absorb a shift indistance to some extent between a distal end of the stick and thefixture position because operating the operation units 1350A and 1350Bwill vary the shift.

It should be noted that the structure of the tip of the connectingsection 1362 and a method for connecting it to the instrument channelwill be explained later.

The mating fixed section 1363, which has the next smaller size than thatof the fixture section 1359 of the stick 1354A, is enclosed in thefixture section 1359 and fixed detachably. In addition, an opening 1364for inserting a procedure instrument therethrough is provided to themating fixed section 1363. The procedure instrument inserted into theopening 1364 and passing through the main body 1361 and the connectingsection 1362 upon entering the instrument channel can reach to the firstarm section 302A.

FIG. 39 is a cross-sectional view showing the stick 1354A having thechannel unit 1360 inserted therein. The slider section 1358 capable ofsliding along the axial line of the main body 1357 is attached to anouter periphery of the main body 1357. An operation member 1365 attachedto the second bending operation mechanism 1353 is attached to the slidersection 1358. For example, the operation member 1365 is formed by a wireinserted through a metal coil, which is not shown in the drawings.Therefore, drawing the slider 1355 enables operation of the secondbending of the first arm section 302A via the second bending operationmechanism 1353. In addition, an erroneous-operation-preventiveconnecting member 1366 attached to the slider section 1358 is insertedthrough the fixture section 1359. The connecting member 1366 providessubstantially the same function and movement as those of the connectionplate 713 explained in the first embodiment, and details thereof will beexplained later.

The fixture section 1359 has a release switch 1367 which releases thefixture between the stick 1354A and the channel unit 1360; an urgingsection 1368 which protrudes the channel unit 1360 when the fixture isreleased; an erroneous-movement-preventive section 1369 which engageswith the connecting member 1366 to regulate the movement of the slidersection 1358; and a removal button 1370 used for removing the procedureinstrument inserted into the channel unit 1360.

A switching member 1367B provided to the release switch 1367 andattached in a through-hole 1367A provided on the upper surface of thefixture section 1359 is capable of sliding in the through-hole 1367A.

A cylinder 1368B inserted into a hole 1368A provided in parallel withthe axial line of the main body 1361 forms the urging section 1368. Sucha structure called a plunger is commonly known. The cylinder 1368B urgedby a spring 1368C is configured to protrude into the inner cavity of thefixture section 1359.

A substantial cylindrical engagement piston 1369B inserted into a hole1369A provided to the bottom surface of the fixture section 1359 formsthe erroneous-movement-preventive section 1369. A spring 1369C urges theengagement piston 1369B upward. The hole 1369A crosses a through-hole1371 having the connecting member 1366 inserted therethroughsubstantially orthogonally. In addition, the engagement piston 1369B isprovided with a through-hole 1372 which communicates with thethrough-hole 1371.

This causes the connecting member 1366 to pass through the through-holes1371 and 1372 and protrude in the vicinity of the fixture section 1359proximally. An upwardly-protruding engagement protrusion 1369C providedin the through-hole 1372 of the engagement piston 1369B is capable ofengaging with an engagement groove, which will be explained later,provided to the connecting member 1366.

On the other hand, the mating fixture section 1363 of the channel unit1360 is provided with engagement jaws 1373 which engage with the stick1354A; a first piston 1374 (regulating section) synchronously movingwith the erroneous-movement-preventive section 1369 to control themovement of the connecting member 1366; and a second piston(falloff-preventive section) 1375 for preventing the inserted procedureinstrument from dropping off of the channel unit 1360 erroneously.

The engagement jaws 1373 urged by a spring to protrude relative to theupper surface of the mating fixed section 1363 is designed to havedimensions which allow the engagement jaws 1373 to be enclosed fully inthe hole 1373A. In addition, the vicinity of the tip is formed to havean oblique surface which facilitates insertion of the channel unit 1360into the stick 1354A.

Therefore, inserting the channel unit 1360 into the stick 1354A causesthe oblique surfaces of the engagement jaws 1373 in the vicinity of thetip to make contact with the fixture section 1359, thereby causing theengagement jaws 1373 to be pushed by the fixture section 1359 andenclosed in the hole 1373A. The engagement jaws 1373 upon reaching thebottom of the through-hole 1367A of the fixture section 1359 movesupward and enters the through-hole 1367A to push the switching member1367B. Accordingly, the engagement between the engagement jaws 1373 andthe through-hole 1367A causes the channel unit 1360 to be detachablyfixed to the stick 1354A.

A spring prevents the first piston 1374 inserted and enclosed in thethrough-hole 1374A from protruding into the inner cavity of the matingfixed section 1363 by urging the first piston 1374. The urging forceacting onto the first piston 1374 is set to be significantly weaker thanthat of the spring 1369C urging the engagement piston 1369B. Thethrough-hole 1374A is provided at a position which providescommunication between the through-hole 1374A and the hole 1369A havingthe engagement piston 1369B inserted therein when the channel unit 1360is fixed to the stick 1354A unitarily. Therefore, fixing the channelunit 1360 to the stick 1354A unitarily causes the first piston 1374 tomake contact with the engagement piston 1369B. In addition, the urgingforce of the spring 1369C causes the first piston 1374 to protrude intothe inner cavity of the mating fixed section 1363. In addition, thelower section of the first piston 1374 pushed downward protrudes belowthe through-hole 1374A allows the engagement piston 1369B to be pusheddown.

In addition, a commonly-known linear bush 1376 is attached to a part ofthe mating fixed section 1363. Bearings, not shown in the drawing,rotatable in the axial line direction in the inner cavity of the linearbush 1376 can provide accurate extension and retraction movement of aninserted procedure instrument along the axial line with less significantforce.

FIG. 40 shows the operation section 1350 in the vicinity of the tip in amagnified view. A channel-fixing section 1377 fixing the connectingsection 1362 provided to the tip of the channel unit 1360 is provided inthe vicinity of the operation section 1350.

The rail 1378 is attached below the channel-fixing section 1377. Therail 1378 engaging with a base 1380 fixed to an enclosure 1379 iscapable of sliding in the longitudinal direction of the rail 1378relative to the base 1380. This allows the channel-fixing section 1377to make extending and retracting movements of a predetermined length.Accordingly, smooth operation can be obtained since the channel-fixingsection 1377 makes extending and retracting movements corresponding tovertical and/or horizontal movements of the two operation sticks 1354Aand 1354B of the operation section 1350.

Movement of the medical treatment endoscope having the aforementionedstructure in use will be explained as follows. The channel unitexplained here in the present embodiment is a sterilized non-recyclableunit 1360A.

FIG. 41 is a perspective view showing the channel unit 1360A. Channelsformed on the outer and inner peripheries of the channel unit 1360A aresterilized by various methods, e.g., autoclave method or a gassterilization method, etc. A first cap 1381 and a second cap 1382 areattached to openings 1364 of the connecting section 1362 and the tubularmain body 1361 respectively to maintain unsterilized condition of thechannels. The first cap 1381 is set to have a diameter that allows thefirst cap 1381 to pass through the inner cavity of the stick 1354A.Screw engagement is provided to the caps 1381 and 1382 attached to thechannel unit 1360. Forming the screw sections engaging with each otherby a metal material improves sterilized condition of the screw sectionsprovided by the autoclave method, etc.

To start with, the channel units 1360A are inserted into the openings ofthe fixture sections 1359 of the sticks 1354A and 1354B. Subsequently,the engagement jaws 1373 are engaged with the through-hole 1367A of therelease switch 1367; and the channel unit 1360A is fixed to the stick1354A unitarily. The method for operating of the stick 1354A explainedas follows is to the stick 1354B connected to the second arm section302B.

Subsequently, the tip of the connecting section 1362 protruding from thetip of the stick 1354A is inserted from an opening formed in thevicinity of the base end of the channel-fixing section 1377 as shown inFIG. 42.

FIG. 43 shows the channel-fixing section 1377 and the connecting section1362 in a cross-sectional view. A fixed knob 1383 provided to thechannel-fixing section 1377 is drawn and the connecting section 1362 isinserted. Subsequently, releasing the fixed knob 1383 upon protrudingthe first cap 1381 from the tip of the channel-fixing section 1377causes the fixed knob 1383 urged by a spring to protrude inward relativeto the channel-fixing section 1377 and engage with the connectingsection 1362. Accordingly, the connecting section 1362 is fixed to thechannel-fixing section 1377 detachably as shown in FIG. 42.

Subsequently, the connecting section 1362 is connected to an instrumentchannel 1384 extending from the endoscope insertion section 503 throughthe connection sheath 515. As shown in FIG. 44, the operation section1350 should be covered with a drape 1304 to prevent a user from touchingthe unsterilized sticks 1354A and 1354B or the whole part of theoperation section.

Subsequently, the boundary part between the first cap 1381 and theconnecting section 1362 is fixed by a tape or a rubber member as shownin FIG. 45. In addition, the outer periphery section of the first cap1381 may be fixed by a tape or a rubber member etc. In addition, theboundary part between the second cap 1382 and the fixture section 1359is fixed similarly. It is preferable that perforation facilitatingseparation thereof should be provided previously to the partcorresponding to the drape 1304 fixed thereon.

As shown in FIG. 46, the user upon separating the drape 1304 along theperforation and removing a part of the drape 1304 and the first cap 1381together from the connecting section 1362 obtains an opening 1385, whichmaintains sterilized condition, formed on the tip of the connectingsection 1362.

Subsequently, inserting a connecting member 1386 provided in thevicinity of the base end of the sterilized instrument channel 1384 intothe opening 1385 and engaging the connecting section 1362 with theconnecting member 1386 cause the channel unit 1360 to connect with theinstrument channel 1384 in a sterilized manner as shown in FIG. 47. Achannel for inserting a procedure instrument in a sterilized conditionthereinto is formed in this manner. The channel communicates from thefirst arm section 302A to the mating fixed section 1363 of the channelunit 1360A. It should be noted that warp of the instrument channel 1384during operation of the procedure instrument is prevented since theconnecting member 1386 attached to the instrument channel 1384 iscapable of freely rotating around the axial line.

Subsequently, a part of the drape 1304 together with the second cap 1382are removed and the opening 1364 of the mating fixed section 1363 isreleased by the same operation as that conducted to the aforementionedfirst cap 1381 to insert the procedure instrument. Subsequently, theprocedure instrument for use inserted into the opening 1364 is protrudedfrom the tip of the first arm section 302A.

FIGS. 48 to 53 show the mating fixed section 1363 of the channel unit1360A and the erroneous-movement-preventive section 1369 of the stick1354A during the insertion of the procedure instrument. A procedureinstrument 1305 specifically used for the medical treatment endoscope1300 has an engagement groove 1305A formed in the circumferentialdirection thereof. The engagement groove 1305A formed to be shallowertoward the base end thereof has a taper surface 1305B. It is preferablethat the engagement groove 1305A be provided so that the tip of theprocedure instrument 1305 may engage with the second piston 1375 uponinserting the tip of the procedure instrument 1305 in the vicinity ofthe tip relative to the second bending of the first arm section.

A first engagement section 1387 and a second engagement section 1388provided to the connecting member 1366 are capable of engaging with theengagement protrusion 1369D of the engagement piston 1369B. The firstengagement section 1387 in the vicinity of the base end has a firstnotch 1387A having a taper surface; and a second notch 1387B formeddeeper than the first notch 1387A and proximal relative to the firstnotch 1387A. A step 1387C having a predetermined, for example, severalmillimeters of depth, is provided between the first notch 1387A and thesecond notch 1387B.

As shown in FIG. 48, the engagement protrusion 1369D of the engagementpiston 1369B engages with the second notch 1387B of the first engagementsection 1387 prior to the insertion of the procedure instrument 1305.The connecting member 1366 in an attempt to draw the slider section 1358in this state proximally cannot move proximally since the engagementprotrusion 1369D abuts to the step 1387C. This prevents bending of thesecond bending of the arm section based on erroneous maneuvering of theslider section 1358 prior to insertion of the procedure instrument 1305into the channel unit 1360A.

It should be noted that the state of first piston 1374 making contactwith the engagement piston 1369B is urged by the spring 1369C andprotruded into the inner cavity of the mating fixed section 1363.

The outer periphery of the procedure instrument 1305 upon inserting theprocedure instrument 1305 into the channel unit 1360A and protruding thesecond piston 1375 into the engagement groove 1305A pushes the firstpiston 1374 downward. The first piston 1374 presses down the engagementpiston 1369B of the erroneous-movement-preventive section 1369. Then theupper end of the engagement protrusion 1369D moves lower than the step1387C. Drawing the slider section 1358 in this state proximally causesthe taper surface of the first notch 1387A to make contact with theengagement protrusion 1369D, thereby allowing the connecting member 1366to move across the engagement protrusion 1369D proximally as shown inFIG. 50. That is, bending operation of the second bending 308 ispossible. This state of engagement groove 1305A of the procedureinstrument 1305 engaging with the second piston 1375 prevents erroneousretraction and drop-off of the slider section 1358 from the channel unit1360A while operating the slider section 1358.

Drawing the slider section 1358 proximally and engaging the secondengagement section 1388 of the connecting member 1366 with theengagement protrusion 1369D as shown in FIG. 51 cause the slider section1358 to be supported by the engagement protrusion 1369D, therebymaintaining the bending state of second bending 308.

Further advancing the procedure instrument 1305 as shown in FIG. 52causes the taper surface 1305B to press down the second piston 1375 andthe tip of the procedure instrument 1305 to protrude from the first armsection 302A, thereby manipulation is ready to be carried out. Thisstate enables extension and retraction of the procedure instrument 1305in the axial line direction. This state of first piston 1374 urgeddownwardly by a spring as shown in FIG. 52 is enclosed in thethrough-hole 1374A since the engagement piston 1369B is moveddownwardly. Therefore, a friction force is not produced between thefirst piston 1374 and the procedure instrument 1305.

Subsequently, desirable manipulation is carried out by the sameoperation as that of the first embodiment by protruding the procedureinstrument from the tip of the second arm section 302B.

Removal of the procedure instrument after ending the manipulationnecessitates pressing the removal button 1370 (see FIG. 39). As shown inFIG. 53, pressing the removal button 1370 causes a first protrusion 1389and a second protrusion 1390 that protrude relative to the outerperiphery of the channel unit 1360 to be pushed down. Pressing down thefirst protrusion 1389 and the second protrusion 1390 extending from thefirst piston 1374 and the second piston 1375 respectively causes thefirst piston 1374 and the second piston 1375 to be pushed down as shownin FIG. 54. The disengagement between the second piston 1375 and theprocedure instrument 1305 consequently enables removal of the procedureinstrument 1305. Simultaneously, the first piston 1374 pushes down theengagement protrusion 1369D of the engagement piston 1369B anddisengages the protrusion 1369D of the engagement piston 1369B from theconnecting member 1366. The tension of the second-bending-operation wirecauses the slider section 1358 to move ahead.

Manipulation using another procedure instrument may be maintained byinsertion of the corresponding procedure instrument in accordance withthe aforementioned method. Operations after ending all the manipulationswill be explained as follows.

After removing the procedure instrument 1305, a lever 1386A (see FIG.47) of the connecting member 1386 of the instrument channel 1384 ismaneuvered to disengage the instrument channel 1384 from the channelunit 1360. Subsequently pulling up the fixed knob of the channel-fixingsection 1377 causes the connecting section 1362 to be removed from thechannel-fixing section 1377.

Subsequently pressing the release switch (see FIG. 39) 1367 causes theengagement jaws 1373 of the mating fixed section 1363 to be disengagedfrom the through-hole 1367A of the release switch 1367. Synchronously,the channel unit 1360A can be removed easily since the urging section1368 pushes the channel unit 1360A proximally and the mating fixedsection 1363 is exposed from the base end of the stick 1354A. Theremoved channel unit 1360A is discarded instantaneously, or cleaned andsterilized for reuse.

The medical treatment endoscope 1300 according to the present embodimentis detachable from the sticks 1354A and 1354B for operating theprocedure instrument 1305 via the arm section and the channel unit 1360including the channel for passing the procedure instrument therethrough.Therefore, manipulations in more sanitary conditions, that maintain thesterilized state of the channels can be conducted by rendering thechannel unit 1360 a sterilized throwaway unit or by sterilization forreuse.

The number of operation units may vary desirably and correspond to thenumber of the arms of the arm section in contrast to the aforementionedembodiment explaining the example in which the operation section isprovided with the first operation unit and the second operation unit.Also, a configuration may be free from the second-bending-wire unit andthe third mating attachment section in a case where the arm section isnot provided with the second bending part 308.

In addition, the position of the releasing switch is not limited to thepresent embodiment explaining an example attaching the release switch1367 onto the upper surface of the fixture section 1359. An examplethereof is as follows.

FIG. 55 is a bottom plan view showing the stick 1391 and the channelunit 1392 in accordance with a modified example of the presentembodiment. FIGS. 56 and 57 are cross-sectional views along the linesA-A and B-B in FIG. 55 respectively.

As shown in FIGS. 55 to 57, the release switch 1393 is separatelydisposed on the bottom surface of the fixture section 1359 above theaxial line in the longitudinal direction of the stick 1391 having theconnecting member 1366 attached thereto. In addition, an oblique surfaceis not formed to the tip of the engagement jaws 1394 provided to thechannel unit 1392. Alternatively, forming an oblique surface on an innerwall 1395A making contact with the engagement jaws 1394 in an opening1395, into which the channel unit 1392 is inserted, facilitatesinsertion of the channel unit 1392 into the stick 1391. Thisconfiguration providing smooth insertion of the channel unit 1392 intothe stick 1391 can also support the both components unitarily.

Also, providing two finger-hook sections 1356 as shown in FIG. 55permits two-hand operation to the slider section, thereby providing easyoperation to a not so muscular user.

In addition, another modified example as shown in FIG. 58 may beprovided in which a connection section 1396 of the channel unit may bescrewed into a connection member 1397 of the instrument channel formedlike a cap in place of the present embodiment explaining an exampleengaging the connection member provided in the vicinity of the base endof the instrument channel with the connecting part of the tip of thechannel unit. Accordingly, possibility of contamination can be reducedmore significantly since an increased-diameter section of the connectionmember 1397 can cover an inner surface 1304A of the drape 1304 whichwill be exposed and contaminated when the drape 1304 is torn.

In addition, inserting the connection section 1396 into, in this case,the channel-fixing section 1377 causes a shaft 1383A connected to thefixed knob 1383 to engage with a groove 1396A provided on the outerperiphery of the connection section 1396. This prevents the connectionsection 1396 from being removed from the channel-fixing section 1377.

Rotating to remove this state of first cap 1381 based on a screwengagement method causes the connection section 1396 to rotate so as toconnect to the procedure instrument channel. Accordingly, the shaft1383A enters one of a plurality of holes 1396B provided to the groove1396A, thereby immobilizing the connection section 1396 to be fixed tothe channel-fixing section 1377 (see FIG. 59). Therefore, attaching theconnection member 1397 to the connection section 1396 by using the screwengagement method is in no need of fixing the connection section 1396manually to prevent the rotation thereof, thereby facilitating theconnection of both components. It should be noted that the hole 1396Bdoes not have to have a through hole formed therethrough as long as thehole 1396B has a recessing shape (recessed section) which is capable ofengaging with the shaft 1383A. For example, the hole 1396B may have abottom having a recessed section.

In addition, as shown in modified examples shown in FIGS. 60A and 60B, afirst cap 1398 and a second cap 1399 may have fixture sections 1398A and1399A which have a reduced diameter on a part of the outer peripheriesrespectively. Accordingly, the drape 1304 can be fixed by, for example,a tape, easily, and a part of the drape 1304 can be removed togetherwith the caps 1398 and 1399.

Third Embodiment

In the medical treatment endoscope according to the present embodiment,a second piston for preventing removal of the procedure instrument 1305is disposed in the vicinity of a tip relative to a first piston linkingwith an erroneous-movement-preventive section.

Structural elements that are equivalent in the following explanationwill be assigned the same numeric symbols and redundant explanationsthereof will be omitted.

FIG. 61 is a perspective view showing a channel unit 1401 in the medicaltreatment endoscope according to the present embodiment. Aside from afew reusable types, the channel unit 1401 undertaking cleaning orsterilization is made of a stainless steel SUS 303 to resist autoclavesterilization. SUS 304 may be used in place of SUS 303. In addition, itis preferable that at least screw engagement portions of a connectingmember 1424 and a mating fixture section 1404 engaging with a first cap1402 and a second cap 1403 respectively for maintaining a sterilizedstate in the channel unit 1401 be made of SUS 303 or 304. Autoclavingmethod in this manner readily provides preferable sterilization to thescrew engagement portions.

The channel unit 1401 is formed so that the connecting member 1424 inthe vicinity of the tip of a metal hardware member has the most reduceddiameter while the diameter increases gradually toward the proximal endso as to provide smooth insertion into an operation stick 1430, whichwill be explained later.

FIG. 62 is a cross-sectional view of the channel unit 1401. A firstpiston 1405 provided to the mating fixture section 1404 and engagingwith a second-bending-link-engagement section 1431 of the operationstick 1430 regulates extension and retraction of a sliding member 1436,which will be explained later, provided to the operation stick 1430 foroperating the second-bending-wire unit 1303. A second piston 1406 forpreventing removal of the procedure instrument 1305 (not shown in thedrawings) inserted in a channel in the channel unit 1401 is provided inthe vicinity of the base end relative to the first piston 1405.

Most of the functions and movements of thesecond-bending-link-engagement section 1431 are the same as those of theerroneous-movement-preventive section 1369 according to the secondembodiment. Different points will be explained later.

A freely rotatable ball 1407 provided to a tip of the second piston 1406protruding into the channel reduces friction produced during extensionand retraction of the procedure instrument 1305 in the channel. Thisresults in reducing operator's burdensome operation, thereby enablingaccurate extension and retraction of the procedure instrument 1305. Highpressure injection of cleaning liquid, etc. into a through-hole 1408provided on the outer periphery of the mating fixture section 1404 andcommunicating to a space in which the second piston 1406 makes a slidingmovement allows the outer periphery of the ball 1407 to be cleaned.

The aforementioned configuration using the example having the separableoperation stick and the channel unit using pistons 1405 and 1406 isapplicable to a configuration using the two components in one unit.

A fixture member 1410 using screw engagement for connecting and fixingthe mating fixture section 1404 to a main body 1409 is attached to a tipof the mating fixture section 1404. A plurality of groves 1410A forfacilitating removal are provided to the fixture member 1410. Asubstantial U-shaped cross section of the inner surface of each grove1410A, orthogonal to the axial line, formed in a curved surface freefrom sharp edges facilitates cleaning thereof. The bearings disposed onthe inner surface of the linear bush 1411 and damaged by chemicals or insterilization processes can be replaced easily since removing thefixture member 1410 allows a linear bush 1411 attached in the matingfixture section 1404 to be taken out.

The main body 1409 connected to the mating fixture section 1404 isprovided with: an outer pipe 1412 forming the outer periphery thereof; achannel pipe 1413 inserted into the outer pipe 1412; a slide pipe 1414attached to the base end of the channel pipe 1413; and a spring 1415urging the slide pipe 1414 toward the base end.

The outer pipe 1412 is a cylindrical member having the tip connected toa connecting section 1416 connected to the instrument channel and thebase end connected to the mating fixture section 1404 via the fixturemember 1410. As shown in FIG. 61, a drain hole 1412A provided on theouter periphery of the outer pipe 1412 provides desirable circulationand drainage of the cleaning liquid injected into the channel unit 1401.

The channel pipe 1413 having a lumen serving as a channel which allowsinsertion of the procedure instrument 1305 therethrough has three pipesincluding a first pipe 1413A, a second pipe 1413B, and a third pipe1413C. The inner diameter of the distally provided first pipe 1413A isgreater than the outer diameter of the second pipe 1413B connected tothe base end thereof allows the second pipe 1413B to extend into thefirst pipe 1413A and allows a part of the second pipe 1413B to beenclosed in the first pipe 1413A. A substantial ring-shape first stopper1417 attached to the base end of the first pipe 1413A as shown in FIG.63 in magnified view and making contact with a second stopper 1418attached to the tip of the second pipe 1413B prevents removal of thesecond pipe 1413B from the first pipe 1413A. Significant clearancesobtained between the inner periphery of the base end of the firststopper 1417 and the second pipe 1413B and between the inner peripheryof the first pipe 1413A and the outer periphery of the second stopper1418 provide smooth extension and retraction of the second pipe 1413B inthe first pipe 1413A. In addition, a taper tip and a taper base end ofthe outer periphery of the first stopper 1417 formed to have graduallyreduced outer diameters prevent the spring 1415 from hooking thereinto.

A third stopper and a fourth stopper (not shown in the drawing) havingthe same shape as the first stopper 1417 and the second stopper 1418 andattached to the base end of the second pipe 1413B and to the tip of thethird pipe 1413C connected respectively allow the third pipe 1413C toextend into the second pipe 1413B, thereby allowing a part of the thirdpipe 1413C to be enclosed in the second pipe 1413B.

The third pipe 1413C slides in the outer pipe 1412 unitarily with theslide pipe 1414 since the base end of the third pipe 1413C fixed to thetip of a member 1420 has a shape allowing the procedure instrument 1305to make contact therewith; and the member 1420 using screw engagement isfixed to the slide pipe 1414. Also, the screw engagement between thethird pipe 1413C and the slide pipe 1414 permits dissembling andcleaning of the two components separately.

The tip of the first pipe 1413A is brazed and fixed to a mouthpiece1419. Visual inspection readily permits observation of a brazed portionseeping from a hole 1419A provided to the mouthpiece 1419.

The outer diameter of the slide pipe 1414 is set to be slightly smallerthan the inner diameter of the outer pipe 1412. The aforementionedmember 1420 attached to a base end 1414A of the slide pipe 1414 causesthe procedure instrument 1305 inserted in the channel unit 1401 to pushthe member 1420, thereby allowing the slide pipe 1414 and the third pipe1413C to move distally. A taper end surface of the tip of the slide pipe1414 having an inner diameter increasing gradually toward the tipprevents hooking of the spring 1415 onto the slide pipe 1414 whilemaking extending and retracting movements in the outer pipe 1412.

The coil spring 1415 made of metal, etc., has a loop having threechannel pipes 1413 inserted therethrough. The spring 1415 is inserted inthe slide pipe 1414. The base end of the spring 1415 making contact witha part having the third pipe 1413C fixed thereto urges the slide pipe1414 to be positioned in the mating fixture section 1404 prior toinsertion of the procedure instrument 1305.

The loop diameter of the spring 1415 is set to be smaller than the innerdiameter of the slide pipe 1414 slightly and greater than the outerdiameter of the channel pipe 1413 significantly so that inconcentricdisposition of the spring 1415 relative to the outer pipe 1412 in theouter pipe 1412 may resist interference with the first stopper 1417.

The connecting section 1416 is connected to the main body 1409 via aflexible tube 1421. The outer periphery of the tube 1421 is coated by acylindrical blade 1422 formed by weaving metal wires. The blade 1422curbing the extension of the tube 1421 in the axial line directionprevents the tube 1421 making extension and contraction from absorbingthe extension and retraction of the procedure instrument, therebyallowing the extension and retraction of the procedure instrument to betransferred to the tip of the procedure instrument reliably.

The tip of the tube 1421 is fixed to a fitting member 1423 fixed byscrew engagement to the connecting member 1424 connecting to theinstrument channel. Adjusting the length of screw engagement between thefitting member 1423 and the connecting member 1424 absorbs variation inlength of the tube 1421 produced while assembling the channel unit 1401,thereby facilitating manufacturing of the channel unit 1401.

The base end of the tube 1421 is fixed to the mouthpiece 1419. A ventvalve 1425 provided between the tube 1421 and the channel pipe 1413 ofthe main body 1409 ensures air-tightness in an area ahead of the channelpipe 1413. A washer 1426 presses and fixes the vent valve 1425 in theaxial line direction of the channel unit 1401. A fastening member 1427engaging with the mouthpiece 1419 by screw engagement fixes the washer1426 and the base end of the tube 1421 onto the vent valve 1425.Accordingly, air-tightness can be maintained reliably since the ventvalve 1425 upon undergoing screw engagement is free from a twistingforce acting thereonto around the axial line.

FIG. 64 is a perspective view showing the operation stick 1430 havingthe channel unit 1401 inserted therethrough. A stainless steel SUJ2 orSUS 420J2 is used to improve the endurance of a pipe 1438 (see FIG. 65)of the operation stick 1430. It is preferable to harden theaforementioned materials to obtain 58 HRC (Rockwell Hardness C-Scale) orgreater if necessary, and it is further preferable to provideanti-corrosion coating, e.g., hard chromium electroplating. This allowsthe first pipe 1413A to resist damage caused by the bearing disposed onthe inner periphery of the linear bush 1436A attached to the slidingmember 1436 which will be explained later.

In addition, the outer periphery of the operation stick 1430 is fullychamfered and formed not to have sharp edge sections which will tear adrape 1034 covering the operation section onto which the operation stick1430 is attached. This configuration prevents an unsterilized sectionfrom being exposed when the medical treatment endoscope is operated.

FIG. 65 is a cross-sectional view showing the operation stick 1430having the channel unit 1401 inserted and fixed therethrough. The outerdiameter of the channel unit 1401 corresponding to the mating fixturesection 1404 is substantially the same as the inner diameter of theoperation stick 1430; thus, the channel unit 1401 makes substantialclose contact with the operation stick 1430.

On the other hand, the outer pipe 1412 of the main body 1409, themouthpiece 1419, and inner periphery of the operation stick 1430 definesa constant clearance G. This provides smooth insertion of the channelunit 1401 into the operation stick 1430 since the aforementionedclearance G absorbs the shift of axial lines between the main body 1409and the mating fixture section 1404. The force applied onto the channelunit 1401 while operating the procedure instrument 1305 is transferredto the operation stick 1430 and the operation section mainly via themating fixture section 1404 disposed in the vicinity of the linear bush1411.

The tip of a crank-shaped connecting member 1432 of thesecond-bending-link-engagement section 1431 is in the vicinity of atubular main body 1433 closely. This configuration will meet fewerinterference between the operation stick 1430 and the enclosure 1379 ofthe operation section during operation thereof since the size of themain body 1433 including the connecting member 1432 in the verticaldirection can be further reduced. In addition, the crank shape of theconnecting member 1432 made of stainless steel SUS 420J2 providesresistance to the bending stress.

A stopper 1435 attached to the connecting member 1432 by screwengagement protrudes toward a fixture section 1434 having thesecond-bending-link-engagement section 1431 provided thereon. Drawingthe sliding member 1436 proximally by a predetermined length causes thetip of the stopper 1435 to make contact with the outer periphery of thefixture section 1434, thereby preventing further proximal retraction ofthe sliding member 1436. This prevents rupture, etc., of the operationmember 1365 for operating the second bending part 308 caused by drawingthe sliding member 1436 excessively. The protrusion of the stopper 1435in length toward the fixture section 1434 is adjustable within apredetermined range by adjusting the screw engagement in length with theconnecting member 1432.

An attachment section 1437 for fixing the operation stick 1430 onto theenclosure 1379 of the operation section is attached to the main body1433. The attachment section 1437 is attached ahead the center of theoperation stick 1430 in the longitudinal direction. The operation stick1430 attached to the enclosure 1379 (not shown in the drawing) andoperated by the procedure instrument 1305 (not shown in the drawing)inserted therethrough swings vertically and horizontally around theattachment section 1437 attached ahead of the tip relative to the centerof the operation stick 1430 in the longitudinal direction reduces theswinging amount of the tip of operation stick 1430, thereby preventinginterference between the two operation sticks for operating thelaterally disposed arm sections 302A and 302B.

FIG. 66 is a perspective view showing the main body 1433 of theoperation stick 1430 in a magnified view. As shown in FIG. 66, theattachment section 1437 and the fixture section 1434 are attached fromthe outside of the pipe 1438 constituting a main part of the main body1433 and fixed thereon. As shown in FIG. 65, the thickness of the tip ofthe pipe 1438 and the thickness of the base end of the pipe 1438 areshallow where steps 1438A and 1438B are provided respectively. Theattachment section 1437 and the fixture section 1434 in the axial linedirection of the pipe 1438 are fixed by inserting the pipe 1438 into alumen from the tip and the base end of the pipe 1438 respectively whileinserting the sliding member 1436 therebetween and making contact withthe step 1438A and 1438B. The position of the attachment section 1437around the axial line of the pipe 1438 and the position of the fixturesection 1434 around the axial line of the pipe 1438 are maintaineddesirably by engaging a fixture screw 1437A protruding into the lumen ofthe attachment section 1437 to a groove 1438C provided to the tip of thepipe 1438 and by engaging a fixture screw 1434A protruding into thelumen of the fixture section 1434 to a groove 1438D provided to the baseend of the pipe 1438 as shown in FIG. 66. The attachment section 1437and the fixture section 1434 positioned in the axial line directionaround the axial line of the pipe 1438 are fixed by: a tip member 1439Aengaged with the tip of the pipe 1438 by screw engagement; a spacer1439B pushed by the tip member 1439A; and a fitting member 1440 engagedwith the base end of the pipe 1438 by screw engagement. This structureallows the attachment section 1437 and the fixture section 1434 to befixed at constant positions around the axial line of the pipe 1438. Inaddition, the attachment section 1437 and the fixture section 1434 canbe fixed to the pipe 1438 reliably by screw engagement while theoperation member 1365 is reliably attached to the operation stick 1430.

As shown in FIG. 66, a silencing member 1441 made of collision-absorbingmaterial, for example, rubber, etc. is attached in the vicinity of thebase end of the attachment section 1437. The silencing member 1441 urgedtoward the base end by a plunger 1442 having substantial the samestructure as that of the urging section 1368 provided to the fixturesection 1434 upon making contact with the sliding member 1436 absorbscollision and prevents large sound when the second bending part 308 ofthe arm section is restored to a linear state and when the slidingmember 1436 is extended. It should be noted that a certain extent ofsilencing effect can be obtained by providing one of the silencingmember 1441 and the plunger 1442.

As shown in FIG. 65, a ball bearing 1445 is attached to the tip of thetip member 1439A for fixing the spacer 1439B. A flange section 1443 isformed by a cap 1446 attached around the outer periphery of the ballbearing 1445. It is preferable that an outer periphery 1446A around theaxial line of the cap 1446 is formed spherical, and it is furtherpreferable that the outer periphery 1446A is formed on the central axisof the cap 1446 so that a sphere substantially coincides with a surfaceof a virtual ball having the center corresponding to a point in themiddle in the axial line direction. This prevents play during operationsince operating the operation stick 1430 in any direction causes theouter periphery 1446A to make point-contact with the enclosure 1379 inthe operation section as shown in FIG. 67.

Pressing a first protrusion 1405A and a second protrusion 1406Asubstantially simultaneously cause the piston 1405 and 1406 to activatesimultaneously since the first protrusion 1405A protruding from thefirst piston 1405 is disposed above the second protrusion 1406Aprotruding from the second piston 1406 in the channel unit 1401according to the present embodiment, and since a step 1447A is providedto a U-shaped hardware 1447 connected to a removal button 1444 providedto the fixture section 1434 of the operation stick 1430.

It should be noted that adjusting the shape of the step 1447A so thatthe first protrusion 1405A can be pressed slightly faster than thesecond protrusion 1406A causes the first piston 1405 to be pushed andcauses the sliding member 1436 to extend distally at first, therebydispose the second bending part 308 of the arm section in linear state.The second piston 1406 pushed subsequently provides removable state tothe procedure instrument 1305, thereby facilitating removal of theprocedure instrument.

The second piston 1406 according to the present embodiment preventsfalloff of the procedure instrument 1305 inserted in the channel unit1401 in the medical treatment endoscope similarly to the aforementionedsecond embodiment. In addition, the sliding member 1436 for operatingthe second bending part 308 of the arm section can be engaged to thesecond-bending-link-engagement section 1431 reliably and supportedthere. In addition, the connecting member 1432 of thesecond-bending-link-engagement section 1431 engaging with an engagementpiston closer to the tip to support the sliding member 1436 reducesdistal protrusion of the connecting member 1432. This results inproviding the more compact operation stick 1430 and facilitating theoperation thereof.

It should be noted that the aforementioned preferred embodiments of thepresent invention do not limit the present invention. The configurationof the present invention allows for additions, omissions, substitutionsand further replacements without departing from the spirit and scope ofthe present invention.

For example, the aforementioned embodiment explaining that the operationmember 1365 for operating the second bending part 308 of the arm sectionis attached to the sliding member 1436 may be replaced by aconfiguration in which an end section of the operation member 1365 isfixed to an end section of a rotatable lever attached to the operationstick. Rotating this case of lever allows the second bending section tobe operated.

Furthermore, it should be noted that the present invention is limited bythe scope of claims attached hereto, and not by the aforementionedexplanations.

What is claimed is:
 1. A medical apparatus comprising: a flexiblesheath; a procedure instrument having a treatment section provided at adistal end of the procedure instrument; an arm section having a firstbending part capable of a bending operation and a first channel capableof inserting the treatment section therethrough and capable ofprotruding therefrom, the arm section being disposed to protrude from atip of the sheath; an operation stick having a second channel connectedto the first channel and inserting the procedure instrumenttherethrough, and a bending operating part connected to the arm sectionby an operation-transmission member; and an operation part provided in aproximal end side of the procedure instrument for operating thetreatment section, wherein the procedure instrument is configured to becapable of moving between a place in which the treatment section isprotruded from the arm section and a predetermined place in the armsection where a whole length of the treatment section is housed insidethe arm section when the procedure instrument is inserted into theoperation stick, wherein the operation stick further comprises: afalloff-preventive section for preventing the operation part of theprocedure instrument from falling off the operation stick, thefalloff-preventive section is arranged at a proximal end side of theoperation stick and is configured to lock and stop movement of theoperation part of the procedure instrument within the operation stickwhen the treatment section is disposed at the predetermined place in thearm section, the first bending part of the arm section is bent bytilting the operation stick in at least one of vertical and horizontaldirections, wherein the falloff-preventive section comprises a pistonenclosed within the operation stick.
 2. The medical apparatus accordingto claim 1, wherein the falloff-preventive section is provided in avicinity of a base end side of the operation stick relative to aregulation section configured to regulate movement of the bendingoperating part.
 3. The medical apparatus according to claim 1, whereinthe second channel formed by a plurality of pipes is capable ofextending and contracting in the operation stick, and a base end of thesecond channel has a shape capable of making contact with a part of theprocedure instrument, and the second channel is contracted by moving theprocedure instrument inserted in the second channel toward a tip of theoperation stick.
 4. The medical apparatus according to claim 1, whereinwhen the procedure instrument is inserted in the second channel, aregulation section configured to regulate movement of the bendingoperating part is moved by the procedure instrument, and regulation tothe bending operating part is released to enable operation of the firstbending part.
 5. The medical apparatus according to claim 1, wherein thebending operating part is a slider capable of sliding and attached to amain body of the operation stick.
 6. The medical apparatus according toclaim 1, wherein the bending operating part is a lever attached to amain body of the operation stick.
 7. The medical apparatus according toclaim 1, wherein the falloff-preventive section is formed to be capableof engaging with an engagement section provided on an outer periphery ofthe procedure instrument.
 8. The medical apparatus according to claim 1,further comprising an observation section, attached to the sheath forobserving an observation object.
 9. The medical apparatus according toclaim 1, wherein the arm section has a second bending part capable of abending operation, the second bending part being disposed at furthertoward a proximal side of the arm section than the first bending part.10. A medical apparatus comprising: a flexible sheath; a procedureinstrument having a treatment section provided at a distal end of theprocedure instrument; an arm section having a first bending part capableof a bending operation and a first channel capable of inserting thetreatment section therethrough and capable of protruding therefrom, thearm section being disposed to protrude from a tip of the sheath; anoperation stick having a bending operating part connected to the armsection by an operation-transmission member; and a channel unit insertedinto the operation stick detachably and having a second channelconnected to the first channel and inserting the procedure instrumenttherethrough; and an operation part provided in a proximal end side ofthe procedure instrument for operating the treatment section; whereinthe procedure instrument is configured to be capable of moving between aplace in which the treatment section is protruded from the arm sectionand a predetermined place in the arm section where a whole length of thetreatment section is housed inside the arm section when the procedureinstrument is inserted into the operation stick, wherein the channelunit further comprises: a falloff-preventive section for preventing theoperation part of the procedure instrument from falling off the channelunit, the falloff-preventive section is arranged at a proximal end sideof the channel unit and is configured to lock and stop movement of theoperation part of the procedure instrument within the channel unit towhen the treatment section is disposed at the predetermined place in thearm section, the first bending part of the arm section is bent bytilting the operation stick in at least one of vertical and horizontaldirections, wherein the falloff-preventive section comprises a pistonenclosed within the operation stick.
 11. The medical apparatus accordingto claim 10, wherein the falloff-preventive section is provided in avicinity of a base end side of the channel unit relative to a regulationsection configured to regulate movement of the bending operating part.12. The medical apparatus according to claim 10, wherein the secondchannel formed by a plurality of pipes is capable of extending andcontracting in the channel unit, and a base end of the second channelhas a shape capable of making contact with a part of the procedureinstrument, and the second channel is contracted by moving the procedureinstrument inserted in the second channel toward a tip of the channelunit.
 13. The medical apparatus according to claim 10, wherein when theprocedure instrument is inserted in the second channel, a regulationsection configured to regulate movement of the bending operating part ismoved by the procedure instrument, and regulation to the bendingoperating part is released to enable operation of the first bendingpart.
 14. The medical apparatus according to claim 10, wherein thebending operating part is a slider capable of sliding and attached to amain body of the operation stick.
 15. The medical apparatus according toclaim 10, wherein the bending operating part is a lever attached to amain body of the operation stick.
 16. The medical apparatus according toclaim 10, wherein the falloff-preventive section is formed to be capableof engaging with an engagement section provided on an outer periphery ofthe procedure instrument.
 17. The medical apparatus according to claim10, further comprising an observation section, attached to the sheathfor observing an observation object.
 18. The medical apparatus accordingto claim 10, wherein the arm section has a second bending part capableof a bending operation, the second bending part being disposed atfurther toward a proximal side of the arm section than the first bendingpart.